PukalskyiI. D. “Nonlocal Neumann Problem for a Degenerate Parabolic Equation”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 9 (September 25, 1999): 1232–1243. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4719.