Recke, Lutz, and Lubomira Softova. “Nonlinear Parabolic Operators With Perturbed Coefficients”. Communications in Mathematics and Applications 9, no. 3 (September 25, 2018): 277–292. Accessed April 6, 2025. http://rgnpublications.com/journals/index.php/cma/article/view/790.