The source code for implementing Spectral subtraction, MMSE-STSA, Wiener filtering are obtained from Esfandiar Zavarehei.
The orginal links for downloading those codes are:
MMSE STSA (https://www.mathworks.com/matlabcentral/fileexchange/10143-mmse-stsa), Retrieved July 23, 2020.
Boll Spectral Subtraction (https://www.mathworks.com/matlabcentral/fileexchange/7675-boll-spectral-subtraction), Retrieved July 23, 2020.
Berouti Spectral Subtraction (https://www.mathworks.com/matlabcentral/fileexchange/7675-boll-spectral-subtraction), Retrieved July 23, 2020.
Wiener Filter (https://www.mathworks.com/matlabcentral/fileexchange/7673-wiener-filter), Retrieved July 23, 2020.
The source code for Wavelet-based denoising: Ref: Islam, Md Tauhidul, et al. "Speech Enhancement Based on Student t Modeling of Teager Energy Operated Perceptual Wavelet Packet Coefficients and a Custom Thresholding Function." IEEE/ACM Transactions on Audio, Speech, and Language Processing 23.11 (2015): 1800-1811.