diff --git a/examples/ECAPA-TDNN/reader.py b/examples/ECAPA-TDNN/reader.py
index 4b66f89..1536b33 100644
--- a/examples/ECAPA-TDNN/reader.py
+++ b/examples/ECAPA-TDNN/reader.py
@@ -1,4 +1,5 @@
 """data process"""
+
 import os
 import pickle
 
diff --git a/examples/ECAPA-TDNN/sampler.py b/examples/ECAPA-TDNN/sampler.py
index f8f5b33..993b0d5 100644
--- a/examples/ECAPA-TDNN/sampler.py
+++ b/examples/ECAPA-TDNN/sampler.py
@@ -1,4 +1,5 @@
 """sampler definition"""
+
 from __future__ import division
 
 import math
diff --git a/examples/ECAPA-TDNN/speaker_verification_cosine.py b/examples/ECAPA-TDNN/speaker_verification_cosine.py
index 431bf7e..ec74227 100644
--- a/examples/ECAPA-TDNN/speaker_verification_cosine.py
+++ b/examples/ECAPA-TDNN/speaker_verification_cosine.py
@@ -1,6 +1,9 @@
+# ECAPA_TDNN in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/recipes/VoxCeleb/SpeakerRec/speaker_verification_cosine.py
 """
 Recipe for training a speaker verification system based on cosine distance.
 """
+
 import datetime
 import os
 import pickle
diff --git a/examples/ECAPA-TDNN/train_speaker_embeddings.py b/examples/ECAPA-TDNN/train_speaker_embeddings.py
index f685a42..eaa4550 100644
--- a/examples/ECAPA-TDNN/train_speaker_embeddings.py
+++ b/examples/ECAPA-TDNN/train_speaker_embeddings.py
@@ -1,6 +1,9 @@
+# Training speaker embeddings in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/recipes/VoxCeleb/SpeakerRec/train_speaker_embeddings.py
 """
 Recipe for training speaker embeddings using the VoxCeleb Dataset.
 """
+
 import math
 import os
 import pickle
diff --git a/examples/ECAPA-TDNN/voxceleb_prepare.py b/examples/ECAPA-TDNN/voxceleb_prepare.py
index 7d27571..4a46a70 100644
--- a/examples/ECAPA-TDNN/voxceleb_prepare.py
+++ b/examples/ECAPA-TDNN/voxceleb_prepare.py
@@ -1,3 +1,5 @@
+# Data preparation in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/recipes/VoxCeleb/SpeakerRec/voxceleb_prepare.py
 """
 Data preparation, from mindaudio VoxCeleb recipe.
 """
diff --git a/examples/conformer/asr_model.py b/examples/conformer/asr_model.py
index a9d7a2d..5436e23 100644
--- a/examples/conformer/asr_model.py
+++ b/examples/conformer/asr_model.py
@@ -1,3 +1,5 @@
+# ASR model in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/asr_model.py
 """Definition of ASR model."""
 
 import mindspore
diff --git a/examples/conformer/predict.py b/examples/conformer/predict.py
index e89f0f6..b6616a6 100644
--- a/examples/conformer/predict.py
+++ b/examples/conformer/predict.py
@@ -1,4 +1,5 @@
-"""ASR inference process.
+"""
+ASR inference process.
 
 python predict.py --config_path <CONFIG_FILE>
 """
diff --git a/examples/conformer/train.py b/examples/conformer/train.py
index 1b20a32..19b4dce 100644
--- a/examples/conformer/train.py
+++ b/examples/conformer/train.py
@@ -1,4 +1,5 @@
-"""ASR training process.
+"""
+ASR training process.
 
 python train.py --config_path <CONFIG_FILE>
 """
diff --git a/examples/conv_tasnet/data.py b/examples/conv_tasnet/data.py
index 3c921a2..f076817 100644
--- a/examples/conv_tasnet/data.py
+++ b/examples/conv_tasnet/data.py
@@ -1,3 +1,5 @@
+# AudioDataLoader in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/data.py
 """
 Logic:
 1. AudioDataLoader generate a minibatch from AudioDataset, the size of this
@@ -16,14 +18,11 @@
     Each targets's shape is B x C x T
 """
 
-import argparse
 import json
 import math
 import os
 
-import mindspore.dataset as ds
 import numpy as np
-from mindspore import context
 
 import mindaudio.data.io as io
 
@@ -176,27 +175,3 @@ def sort_and_pad(self, batch):
 
         sources_pad = sources_pad.transpose((0, 2, 1))
         return mixtures_pad, ilens, sources_pad
-
-
-if __name__ == "__main__":
-    context.set_context(mode=context.GRAPH_MODE, device_target="Ascend", device_id=4)
-    args = parser.parse_args()
-    print(args)
-    tr_dataset = DatasetGenerator(
-        args.train_dir,
-        args.batch_size,
-        sample_rate=args.sample_rate,
-        segment=args.segment,
-    )
-    dataset = ds.GeneratorDataset(
-        tr_dataset, ["mixture", "lens", "sources"], shuffle=False
-    )
-    dataset = dataset.batch(batch_size=5)
-    iter_per_epoch = dataset.get_dataset_size()
-    print(iter_per_epoch)
-    h = 0
-    for data in dataset.create_dict_iterator():
-        h += 1
-        print(data["mixture"])
-        print(data["lens"])
-        print(data["sources"])
diff --git a/examples/conv_tasnet/eval.py b/examples/conv_tasnet/eval.py
index d21391f..ba913c2 100644
--- a/examples/conv_tasnet/eval.py
+++ b/examples/conv_tasnet/eval.py
@@ -1,3 +1,6 @@
+# Evaluation of Conv-TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/evaluate.py
+
 import mindspore
 import mindspore.dataset as ds
 import mindspore.ops as ops
diff --git a/examples/conv_tasnet/preprocess.py b/examples/conv_tasnet/preprocess.py
index b6ee267..2401033 100644
--- a/examples/conv_tasnet/preprocess.py
+++ b/examples/conv_tasnet/preprocess.py
@@ -1,3 +1,5 @@
+# Preprocess of Conv-TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/preprocess.py
 """ Convert the relevant information in the audio wav file to a json file """
 
 import argparse
diff --git a/examples/conv_tasnet/train.py b/examples/conv_tasnet/train.py
index 9c021fc..b9377dc 100644
--- a/examples/conv_tasnet/train.py
+++ b/examples/conv_tasnet/train.py
@@ -1,3 +1,6 @@
+# Train of Conv-TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/train.py
+
 import os
 
 import mindspore.dataset as ds
diff --git a/examples/deepspeech2/eval.py b/examples/deepspeech2/eval.py
index 70cc725..0412118 100644
--- a/examples/deepspeech2/eval.py
+++ b/examples/deepspeech2/eval.py
@@ -1,3 +1,5 @@
+# Evaluation of deepspeech2 in mindspore.
+# Adapted from https://github.com/SeanNaren/deepspeech.pytorch/tree/master/deepspeech_pytorch/validation.py
 """
 Eval DeepSpeech2
 """
diff --git a/examples/deepspeech2/train.py b/examples/deepspeech2/train.py
index 4c01086..a4f364b 100644
--- a/examples/deepspeech2/train.py
+++ b/examples/deepspeech2/train.py
@@ -1,3 +1,5 @@
+# Train of deepspeech2 in mindspore.
+# Adapted from https://github.com/SeanNaren/deepspeech.pytorch/tree/master/deepspeech_pytorch/training.py
 """train_criteo."""
 
 import os
diff --git a/examples/fastspeech2/dataset.py b/examples/fastspeech2/dataset.py
index 35a4e35..7e58d0c 100755
--- a/examples/fastspeech2/dataset.py
+++ b/examples/fastspeech2/dataset.py
@@ -1,3 +1,6 @@
+# LJSpeech dataloader in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/dataset.py
+
 import os
 import sys
 from multiprocessing import cpu_count
diff --git a/examples/fastspeech2/generate.py b/examples/fastspeech2/generate.py
index 775a2a4..c4555c8 100644
--- a/examples/fastspeech2/generate.py
+++ b/examples/fastspeech2/generate.py
@@ -1,3 +1,6 @@
+# Synthesize in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/synthesize.py
+
 import argparse
 import os
 import re
diff --git a/examples/fastspeech2/ljspeech.py b/examples/fastspeech2/ljspeech.py
index 9f73c88..4d07ec8 100755
--- a/examples/fastspeech2/ljspeech.py
+++ b/examples/fastspeech2/ljspeech.py
@@ -1,3 +1,6 @@
+# LJSpeech dataloader in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/preprocessor/ljspeech.py
+
 import csv
 import os
 
diff --git a/examples/fastspeech2/preprocess.py b/examples/fastspeech2/preprocess.py
index c2a6d93..137a1cb 100755
--- a/examples/fastspeech2/preprocess.py
+++ b/examples/fastspeech2/preprocess.py
@@ -1,5 +1,6 @@
 # Given the path to ljspeech/wavs,
 # this script converts wav files to .npy features used for training.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/preprocessor/preprocessor.py
 
 import argparse
 import os
diff --git a/examples/fastspeech2/text/__init__.py b/examples/fastspeech2/text/__init__.py
index 25b3330..ca49065 100644
--- a/examples/fastspeech2/text/__init__.py
+++ b/examples/fastspeech2/text/__init__.py
@@ -1,4 +1,4 @@
-""" from https://github.com/keithito/tacotron """
+# Copited from from https://github.com/keithito/tacotron
 import re
 
 from text import cleaners
diff --git a/examples/fastspeech2/text/cleaners.py b/examples/fastspeech2/text/cleaners.py
index 399b853..515651c 100644
--- a/examples/fastspeech2/text/cleaners.py
+++ b/examples/fastspeech2/text/cleaners.py
@@ -1,4 +1,4 @@
-""" from https://github.com/keithito/tacotron """
+# Copited from https://github.com/keithito/tacotron
 
 """
 Cleaners are transformations that run over the input text at both training and eval time.
diff --git a/examples/fastspeech2/text/cmudict.py b/examples/fastspeech2/text/cmudict.py
index 9858827..c566b99 100644
--- a/examples/fastspeech2/text/cmudict.py
+++ b/examples/fastspeech2/text/cmudict.py
@@ -1,4 +1,4 @@
-""" from https://github.com/keithito/tacotron """
+# Copited from https://github.com/keithito/tacotron
 
 import re
 
diff --git a/examples/fastspeech2/text/numbers.py b/examples/fastspeech2/text/numbers.py
index d5cf986..ce9641c 100644
--- a/examples/fastspeech2/text/numbers.py
+++ b/examples/fastspeech2/text/numbers.py
@@ -1,4 +1,4 @@
-""" from https://github.com/keithito/tacotron """
+# Copited from https://github.com/keithito/tacotron
 
 import re
 
diff --git a/examples/fastspeech2/text/pinyin.py b/examples/fastspeech2/text/pinyin.py
index b590081..71ae5e8 100644
--- a/examples/fastspeech2/text/pinyin.py
+++ b/examples/fastspeech2/text/pinyin.py
@@ -1,3 +1,5 @@
+# Copited from https://github.com/ming024/FastSpeech2/blob/master/text/pinyin.py
+
 initials = [
     "b",
     "c",
diff --git a/examples/fastspeech2/text/symbols.py b/examples/fastspeech2/text/symbols.py
index 426d2d6..4fdbe75 100644
--- a/examples/fastspeech2/text/symbols.py
+++ b/examples/fastspeech2/text/symbols.py
@@ -1,3 +1,5 @@
+# Copited from https://github.com/ming024/FastSpeech2/blob/master/text/symbols.py
+
 from text import pinyin
 
 valid_symbols = [
diff --git a/examples/fastspeech2/train.py b/examples/fastspeech2/train.py
index fd7b56b..834f276 100755
--- a/examples/fastspeech2/train.py
+++ b/examples/fastspeech2/train.py
@@ -1,3 +1,6 @@
+# Training in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/train.py
+
 import argparse
 import ast
 import os
diff --git a/examples/tasnet/data.py b/examples/tasnet/data.py
index 87364e8..a5ed0e3 100644
--- a/examples/tasnet/data.py
+++ b/examples/tasnet/data.py
@@ -1,4 +1,6 @@
-""" data """
+# AudioDataLoader in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/data.py
+
 import json
 import os
 
diff --git a/examples/tasnet/eval.py b/examples/tasnet/eval.py
index 67afb63..b3130ac 100644
--- a/examples/tasnet/eval.py
+++ b/examples/tasnet/eval.py
@@ -1,3 +1,6 @@
+# Evaluation of TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/evaluate.py
+
 import argparse
 import json
 import os
@@ -6,14 +9,7 @@
 import mindspore.dataset as ds
 import mindspore.ops as ops
 from data import DatasetGenerator
-from mindspore import (
-    Parameter,
-    Tensor,
-    context,
-    load_checkpoint,
-    load_param_into_net,
-    set_seed,
-)
+from mindspore import context, load_checkpoint, load_param_into_net, set_seed
 
 import mindaudio.data.io as io
 from mindaudio.loss.separation_loss import Separation_Loss
diff --git a/examples/tasnet/preprocess.py b/examples/tasnet/preprocess.py
index ee29712..2dff787 100755
--- a/examples/tasnet/preprocess.py
+++ b/examples/tasnet/preprocess.py
@@ -1,3 +1,5 @@
+# Preprocess of TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/preprocess.py
 """ Convert the relevant information in the audio wav file to a json file """
 
 import argparse
diff --git a/examples/tasnet/train.py b/examples/tasnet/train.py
index ec6d58d..ecf3522 100644
--- a/examples/tasnet/train.py
+++ b/examples/tasnet/train.py
@@ -1,4 +1,6 @@
-""" Train """
+# Training of TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/train.py
+
 import argparse
 import json
 import os
diff --git a/examples/tasnet/train_wrapper.py b/examples/tasnet/train_wrapper.py
index 9a20996..64587d8 100644
--- a/examples/tasnet/train_wrapper.py
+++ b/examples/tasnet/train_wrapper.py
@@ -1,4 +1,5 @@
 """ Training Wrapper """
+
 import mindspore.nn as nn
 import mindspore.ops as ops
 from mindspore import context
diff --git a/examples/wavegrad/dataset.py b/examples/wavegrad/dataset.py
index 5caca6c..ec90334 100644
--- a/examples/wavegrad/dataset.py
+++ b/examples/wavegrad/dataset.py
@@ -1,3 +1,6 @@
+# AudioDataLoader in mindspore.
+# Adapted from https://github.com/lmnt-com/wavegrad/blob/master/src/wavegrad/dataset.py
+
 from multiprocessing import cpu_count
 
 import numpy as np
diff --git a/examples/wavegrad/ljspeech.py b/examples/wavegrad/ljspeech.py
index 9f73c88..4d07ec8 100755
--- a/examples/wavegrad/ljspeech.py
+++ b/examples/wavegrad/ljspeech.py
@@ -1,3 +1,6 @@
+# LJSpeech dataloader in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/preprocessor/ljspeech.py
+
 import csv
 import os
 
diff --git a/examples/wavegrad/preprocess.py b/examples/wavegrad/preprocess.py
index 17eac81..8c2255d 100755
--- a/examples/wavegrad/preprocess.py
+++ b/examples/wavegrad/preprocess.py
@@ -1,3 +1,6 @@
+# Preprocess in mindspore.
+# Adapted from https://github.com/lmnt-com/wavegrad/blob/master/src/wavegrad/preprocess.py
+
 import sys
 from multiprocessing import Pool, cpu_count
 
diff --git a/mindaudio/data/aishell.py b/mindaudio/data/aishell.py
index c21117c..370b629 100644
--- a/mindaudio/data/aishell.py
+++ b/mindaudio/data/aishell.py
@@ -1,3 +1,6 @@
+# AISHELL dataloader in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/recipes/AISHELL-1/aishell_prepare.py
+
 import argparse
 import csv
 import glob
diff --git a/mindaudio/data/augment.py b/mindaudio/data/augment.py
index 968af82..58c143d 100644
--- a/mindaudio/data/augment.py
+++ b/mindaudio/data/augment.py
@@ -1,3 +1,6 @@
+# Time-Domain Sequential Data Augmentation Classes
+# Adapted from  https://github.com/speechbrain/speechbrain/blob/develop/speechbrain/augment/time_domain.py
+
 import random
 
 import mindspore as ms
diff --git a/mindaudio/data/features.py b/mindaudio/data/features.py
index b06dec4..de091f7 100644
--- a/mindaudio/data/features.py
+++ b/mindaudio/data/features.py
@@ -1,3 +1,6 @@
+# Feature extraction
+# Adapted from  https://github.com/librosa/librosa/tree/main/librosa/feature/spectral.py
+
 import mindspore as ms
 import mindspore.dataset.audio as msaudio
 import numpy as np
diff --git a/mindaudio/data/filters.py b/mindaudio/data/filters.py
index 77a9386..62db3fb 100644
--- a/mindaudio/data/filters.py
+++ b/mindaudio/data/filters.py
@@ -1,3 +1,8 @@
+# Filter bank construction
+# Adapted from https://github.com/librosa/librosa/tree/main/librosa/filters.py
+# and
+# https://github.com/speechbrain/speechbrain/blob/develop/speechbrain/processing/signal_processing.py
+
 from typing import Optional, Union
 
 try:
diff --git a/mindaudio/data/io.py b/mindaudio/data/io.py
index 4b6d6a5..d675a54 100644
--- a/mindaudio/data/io.py
+++ b/mindaudio/data/io.py
@@ -1,3 +1,6 @@
+# Module to read / write wav files using NumPy arrays
+# Adapted from  https://github.com/scipy/scipy/tree/main/scipy/io/wavfile.py
+
 import collections
 import io
 import struct
diff --git a/mindaudio/data/librispeech.py b/mindaudio/data/librispeech.py
index 7f433ef..417f93e 100644
--- a/mindaudio/data/librispeech.py
+++ b/mindaudio/data/librispeech.py
@@ -1,3 +1,6 @@
+# LibriSpeech dataloader in mindspore.
+# Adapted from https://github.com/SeanNaren/deepspeech.pytorch/tree/master/data/librispeech.py
+
 import argparse
 import json
 import os
diff --git a/mindaudio/data/processing.py b/mindaudio/data/processing.py
index d4a60f3..7f94687 100644
--- a/mindaudio/data/processing.py
+++ b/mindaudio/data/processing.py
@@ -1,3 +1,8 @@
+# Signal processing utilities
+# Adapted from  https://github.com/librosa/librosa/tree/main/librosa/core/audio.py
+# and
+# https://github.com/facebookresearch/AugLy/blob/main/augly/audio/functional.py
+
 import math
 
 import mindspore as ms
diff --git a/mindaudio/data/spectrum.py b/mindaudio/data/spectrum.py
index ec66ef2..82091ed 100644
--- a/mindaudio/data/spectrum.py
+++ b/mindaudio/data/spectrum.py
@@ -1,3 +1,5 @@
+# Adapted from  https://github.com/librosa/librosa/tree/main/librosa/core/spectrum.py
+
 import mindspore as ms
 import mindspore.dataset.audio as msaudio
 import numpy as np
diff --git a/mindaudio/data/voxceleb.py b/mindaudio/data/voxceleb.py
index cad01a7..280faa7 100644
--- a/mindaudio/data/voxceleb.py
+++ b/mindaudio/data/voxceleb.py
@@ -1,3 +1,5 @@
+# Voxceleb dataloader in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/recipes/VoxCeleb/voxceleb_prepare.py
 """
 Data preparation, from mindaudio VoxCeleb recipe.
 """
diff --git a/mindaudio/loss/AdditiveAngularMargin.py b/mindaudio/loss/AdditiveAngularMargin.py
index ea2e405..533c465 100644
--- a/mindaudio/loss/AdditiveAngularMargin.py
+++ b/mindaudio/loss/AdditiveAngularMargin.py
@@ -1,3 +1,6 @@
+# AdditiveAngularMargin in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/speechbrain/nnet/losses.py
+
 import math
 
 import mindspore as ms
diff --git a/mindaudio/loss/ctc_loss.py b/mindaudio/loss/ctc_loss.py
index f513951..cb94c9c 100644
--- a/mindaudio/loss/ctc_loss.py
+++ b/mindaudio/loss/ctc_loss.py
@@ -1,3 +1,5 @@
+# CTC in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/ctc.py
 """CTC layer."""
 
 import mindspore
diff --git a/mindaudio/loss/label_smoothing_loss.py b/mindaudio/loss/label_smoothing_loss.py
index 8e1542a..edd17c7 100644
--- a/mindaudio/loss/label_smoothing_loss.py
+++ b/mindaudio/loss/label_smoothing_loss.py
@@ -1,3 +1,5 @@
+# Label_smoothing_loss in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/label_smoothing_loss.py
 """Label smoothing module."""
 
 import mindspore
diff --git a/mindaudio/loss/separation_loss.py b/mindaudio/loss/separation_loss.py
index 34bc0af..484b0fd 100644
--- a/mindaudio/loss/separation_loss.py
+++ b/mindaudio/loss/separation_loss.py
@@ -1,4 +1,7 @@
+# Separation_loss in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/pit_criterion.py
 """ Loss """
+
 from itertools import permutations
 
 import mindspore
diff --git a/mindaudio/metric/snr.py b/mindaudio/metric/snr.py
index 55a19c8..48b6818 100644
--- a/mindaudio/metric/snr.py
+++ b/mindaudio/metric/snr.py
@@ -1,3 +1,6 @@
+# SNR in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/evaluate.py
+
 import numpy as np
 from mir_eval.separation import bss_eval_sources
 
diff --git a/mindaudio/models/conformer.py b/mindaudio/models/conformer.py
index 5b41801..3714c07 100644
--- a/mindaudio/models/conformer.py
+++ b/mindaudio/models/conformer.py
@@ -1,4 +1,6 @@
-"""Definition of ASR model."""
+# Conformer in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer
+"""Definition of conformer model."""
 
 from typing import Optional, Tuple
 
diff --git a/mindaudio/models/conv_tasnet.py b/mindaudio/models/conv_tasnet.py
index 22fc4cc..af2a9d5 100644
--- a/mindaudio/models/conv_tasnet.py
+++ b/mindaudio/models/conv_tasnet.py
@@ -1,3 +1,6 @@
+# Conv-TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/Conv-TasNet/blob/master/src/conv_tasnet.py
+
 import argparse
 import math
 
diff --git a/mindaudio/models/decoders/decoder_factory.py b/mindaudio/models/decoders/decoder_factory.py
index 4d112f0..117d82a 100644
--- a/mindaudio/models/decoders/decoder_factory.py
+++ b/mindaudio/models/decoders/decoder_factory.py
@@ -1,3 +1,5 @@
+# Search in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet
 """Prediction net for ASR inference."""
 
 import mindspore
diff --git a/mindaudio/models/decoders/greedydecoder.py b/mindaudio/models/decoders/greedydecoder.py
index a11e478..8062803 100644
--- a/mindaudio/models/decoders/greedydecoder.py
+++ b/mindaudio/models/decoders/greedydecoder.py
@@ -1,3 +1,6 @@
+# Greedydecoder of deepspeech2 in mindspore.
+# Adapted from https://github.com/SeanNaren/deepspeech.pytorch/tree/master/src/deepspeech_pytorch/decoder.py
+
 import Levenshtein as Lev
 import numpy as np
 from six.moves import xrange
diff --git a/mindaudio/models/deepspeech2.py b/mindaudio/models/deepspeech2.py
index 84e377e..89d59b2 100644
--- a/mindaudio/models/deepspeech2.py
+++ b/mindaudio/models/deepspeech2.py
@@ -1,6 +1,5 @@
-"""
-DeepSpeech2 model
-"""
+# DeepSpeech2 model in mindspore.
+# Adapted from https://github.com/SeanNaren/deepspeech.pytorch/tree/master/src/deepspeech_pytorch/model.py
 
 import math
 
diff --git a/mindaudio/models/ecapatdnn.py b/mindaudio/models/ecapatdnn.py
index c69113d..fc5b37b 100644
--- a/mindaudio/models/ecapatdnn.py
+++ b/mindaudio/models/ecapatdnn.py
@@ -1,3 +1,6 @@
+# ECAPA_TDNN in mindspore.
+# Adapted from https://github.com/speechbrain/speechbrain/blob/develop/speechbrain/lobes/models/ECAPA_TDNN.py
+
 import mindspore as ms
 import mindspore.nn as nn
 import mindspore.ops as ops
diff --git a/mindaudio/models/fastspeech2/fastspeech2_v190.py b/mindaudio/models/fastspeech2/fastspeech2_v190.py
index 30bcc3b..9ace938 100755
--- a/mindaudio/models/fastspeech2/fastspeech2_v190.py
+++ b/mindaudio/models/fastspeech2/fastspeech2_v190.py
@@ -1,3 +1,6 @@
+# FastSpeech2 in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/model/fastspeech2.py
+
 import mindspore as ms
 import mindspore.nn as nn
 import numpy as np
diff --git a/mindaudio/models/fastspeech2/loss.py b/mindaudio/models/fastspeech2/loss.py
index 5a11470..0b49c0f 100644
--- a/mindaudio/models/fastspeech2/loss.py
+++ b/mindaudio/models/fastspeech2/loss.py
@@ -1,3 +1,6 @@
+# FastSpeech2Loss in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/model/loss.py
+
 import mindspore as ms
 import mindspore.nn as nn
 import mindspore.ops as ops
diff --git a/mindaudio/models/fastspeech2/variance_adapter.py b/mindaudio/models/fastspeech2/variance_adapter.py
index ba8ecc8..e0f81eb 100644
--- a/mindaudio/models/fastspeech2/variance_adapter.py
+++ b/mindaudio/models/fastspeech2/variance_adapter.py
@@ -1,3 +1,6 @@
+# VarianceAdaptor with mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/model/modules.py
+
 import mindspore as ms
 import mindspore.nn as nn
 import numpy as np
diff --git a/mindaudio/models/layers/attention.py b/mindaudio/models/layers/attention.py
index c8d20e2..34c4540 100644
--- a/mindaudio/models/layers/attention.py
+++ b/mindaudio/models/layers/attention.py
@@ -1,3 +1,5 @@
+# Attention in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/attention.py
 """Multi-Head Attention layer definition."""
 
 import math
diff --git a/mindaudio/models/layers/cmvn.py b/mindaudio/models/layers/cmvn.py
index 9f12c55..4977cbb 100644
--- a/mindaudio/models/layers/cmvn.py
+++ b/mindaudio/models/layers/cmvn.py
@@ -1,3 +1,5 @@
+# CMVN in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/cmvn.py
 """cepstral mean and variance normalization definition."""
 
 import mindspore
diff --git a/mindaudio/models/layers/convolution.py b/mindaudio/models/layers/convolution.py
index ddec673..ff08d8b 100644
--- a/mindaudio/models/layers/convolution.py
+++ b/mindaudio/models/layers/convolution.py
@@ -1,3 +1,5 @@
+# Convolution in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/convolution.py
 """ConvolutionModule definition."""
 
 from typing import Tuple
diff --git a/mindaudio/models/layers/embedding.py b/mindaudio/models/layers/embedding.py
index eba552f..84717ab 100644
--- a/mindaudio/models/layers/embedding.py
+++ b/mindaudio/models/layers/embedding.py
@@ -1,3 +1,5 @@
+# Embedding in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/embedding.py
 """Positonal Encoding Module."""
 
 import math
diff --git a/mindaudio/models/layers/positionwise_feed_forward.py b/mindaudio/models/layers/positionwise_feed_forward.py
index 4eb664b..332908f 100644
--- a/mindaudio/models/layers/positionwise_feed_forward.py
+++ b/mindaudio/models/layers/positionwise_feed_forward.py
@@ -1,4 +1,7 @@
+# Positionwise feed forward in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/positionwise_feed_forward.py
 """Positionwise feed forward layer definition."""
+
 import mindspore
 import mindspore.common.dtype as mstype
 import mindspore.nn as nn
diff --git a/mindaudio/models/layers/subsampling.py b/mindaudio/models/layers/subsampling.py
index 63b041f..31abebd 100644
--- a/mindaudio/models/layers/subsampling.py
+++ b/mindaudio/models/layers/subsampling.py
@@ -1,3 +1,5 @@
+# Subsampling in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/subsampling.py
 """Subsampling layer definition."""
 
 import mindspore
diff --git a/mindaudio/models/layers/swish.py b/mindaudio/models/layers/swish.py
index 4501c08..717166f 100644
--- a/mindaudio/models/layers/swish.py
+++ b/mindaudio/models/layers/swish.py
@@ -1,3 +1,5 @@
+# Swish in mindspore.
+# Adapted from https://github.com/wenet-e2e/wenet/blob/main/wenet/transformer/swish.py
 """Swish() activation function for Conformer."""
 
 import mindspore
diff --git a/mindaudio/models/tasnet.py b/mindaudio/models/tasnet.py
index 168c29d..c3740d5 100644
--- a/mindaudio/models/tasnet.py
+++ b/mindaudio/models/tasnet.py
@@ -1,4 +1,6 @@
-""" TasNet """
+# TasNet in mindspore.
+# Adapted from https://github.com/kaituoxu/TasNet/blob/master/src/tasnet.py
+
 import mindspore
 from mindspore import nn, ops
 
diff --git a/mindaudio/models/transformer/constants.py b/mindaudio/models/transformer/constants.py
index 757d116..23d0edb 100644
--- a/mindaudio/models/transformer/constants.py
+++ b/mindaudio/models/transformer/constants.py
@@ -1,4 +1,7 @@
+# Constants in mindspore.
+# Copited from https://github.com/ming024/FastSpeech2/blob/master/transformer/Constants.py
 """Constants and tokens."""
+
 PAD = 0
 UNK = 1
 BOS = 2
diff --git a/mindaudio/models/transformer/layers.py b/mindaudio/models/transformer/layers.py
index 9accb3f..f00bf57 100644
--- a/mindaudio/models/transformer/layers.py
+++ b/mindaudio/models/transformer/layers.py
@@ -1,3 +1,6 @@
+# Layers in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/transformer/Layers.py
+
 from mindspore import nn
 
 from mindaudio.models.transformer.sublayers import (
diff --git a/mindaudio/models/transformer/models.py b/mindaudio/models/transformer/models.py
index d425907..ff4068c 100644
--- a/mindaudio/models/transformer/models.py
+++ b/mindaudio/models/transformer/models.py
@@ -1,3 +1,6 @@
+# Models in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/transformer/Models.py
+
 from mindspore import Tensor
 from mindspore import dtype as mstype
 from mindspore import nn, ops
diff --git a/mindaudio/models/transformer/score_function.py b/mindaudio/models/transformer/score_function.py
index 0d6a37a..04f6469 100644
--- a/mindaudio/models/transformer/score_function.py
+++ b/mindaudio/models/transformer/score_function.py
@@ -1,3 +1,6 @@
+# ScaledDotProductAttention in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/transformer/Modules.py
+
 import mindspore.numpy as msnp
 from mindspore import nn, ops
 
diff --git a/mindaudio/models/transformer/sublayers.py b/mindaudio/models/transformer/sublayers.py
index f8b881f..c4ff353 100644
--- a/mindaudio/models/transformer/sublayers.py
+++ b/mindaudio/models/transformer/sublayers.py
@@ -1,3 +1,6 @@
+# Sublayers in mindspore.
+# Adapted from https://github.com/ming024/FastSpeech2/blob/master/transformer/SubLayers.py
+
 import numpy as np
 from mindspore import dtype as mstype
 from mindspore import nn, ops
diff --git a/mindaudio/models/wavegrad/wavegrad_v190.py b/mindaudio/models/wavegrad/wavegrad_v190.py
index 01d19cb..d502a98 100644
--- a/mindaudio/models/wavegrad/wavegrad_v190.py
+++ b/mindaudio/models/wavegrad/wavegrad_v190.py
@@ -1,6 +1,5 @@
-"""
-THIS FILE IS FOR MindSpore 1.9
-"""
+# WaveGrad in mindspore.
+# Adapted from https://github.com/lmnt-com/wavegrad/blob/master/src/wavegrad/model.py
 
 from math import log as ln
 
diff --git a/mindaudio/utils/initializer.py b/mindaudio/utils/initializer.py
index 4a3fde2..181d068 100644
--- a/mindaudio/utils/initializer.py
+++ b/mindaudio/utils/initializer.py
@@ -1,4 +1,16 @@
-"""initializer function"""
+# Licensed under the Apache License, Version 2.0 (the "License");
+# Adapted from https://github.com/mlcommons/training_results_v0.7
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# =============================================================================
 
 import math
 
diff --git a/mindaudio/utils/load_files.py b/mindaudio/utils/load_files.py
index 61944d6..b358de3 100644
--- a/mindaudio/utils/load_files.py
+++ b/mindaudio/utils/load_files.py
@@ -1,3 +1,17 @@
+# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
+#
+# Adapted from https://github.com/PaddleSpeech/paddlespeech
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 """Define cmvn-related methods."""
 
 import json
diff --git a/mindaudio/utils/mask.py b/mindaudio/utils/mask.py
index 390570e..080fc86 100644
--- a/mindaudio/utils/mask.py
+++ b/mindaudio/utils/mask.py
@@ -1,3 +1,17 @@
+# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
+#
+# Adapted from https://github.com/PaddleSpeech/paddlespeech
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 """mask function"""
 
 from typing import List
diff --git a/mindaudio/utils/recognize.py b/mindaudio/utils/recognize.py
index 175947b..b73d94e 100644
--- a/mindaudio/utils/recognize.py
+++ b/mindaudio/utils/recognize.py
@@ -1,4 +1,18 @@
-"""Apply beam search on attention decoder."""
+# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
+#
+# Adapted from https://github.com/PaddleSpeech/paddlespeech
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 
 from collections import defaultdict
 
diff --git a/mindaudio/utils/text2token.py b/mindaudio/utils/text2token.py
index 054aac4..f270e9c 100755
--- a/mindaudio/utils/text2token.py
+++ b/mindaudio/utils/text2token.py
@@ -1,4 +1,7 @@
-"""Cut text into single words."""
+# Copyright 2017 Johns Hopkins University (Shinji Watanabe)
+# Adapted from https://github.com/espnet/espnet/tree/master/utils/text2token.py
+#  Apache 2.0  (http://www.apache.org/licenses/LICENSE-2.0)
+
 
 from __future__ import print_function, unicode_literals