Schechter, E. “The Generalized Solution of a Nonlinear Degenerate Parabolic Equation and Its Numerical Computation”. Anal. Numér. Théor. Approx., vol. 13, no. 1, Feb. 1984, pp. 73-93, https://ictp.acad.ro/jnaat/journal/article/view/1984-vol13-no1-art9.