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).
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).