Monophonic and Polyphonic Wheezing Classification Based on Constrained Low-Rank Non-Negative Matrix Factorization. - Juan De La Torre Cruz; Francisco Jesús Cañadas-Quesada; Nicolás Ruiz-Reyes; Sebastián García Galán; Julio José Carabias-Orti; Gerardo Peréz Chica (Sensors, 2021)