Kajikiya, Ryuji. “Non-Radial Solutions With Orthogonal Subgroup Invariance for Semilinear Dirichlet Problems”. Topological Methods in Nonlinear Analysis 21, no. 1 (March 1, 2003): 41–51. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2003.003.