1
For a theoretical overview see the paper “Noise Reduction Based on Modified Spectral Subtraction Method” by Ekaterina Verteletskaya and Boris Simak (2011), International Journal of Computer Science, 38:1 (PDF).
2
For details see Section 3A of the paper “Speech Enhancement using Spectral Subtraction-type Algorithms: A Comparison and Simulation Study” by Navneet Upadhyay and Abhijit Karmakar (2015), Procedia Computer Science, vol. 54, pp. 574–584 (PDF).