Larin, D. V., and I. V. Skrypnik. “Principle of Additivity in Averaging of Degenerate Nonlinear Dirichlet Problems”. Ukrains’kyi Matematychnyi Zhurnal 50, no. 1 (January 25, 1998): 118–135. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4977.