Shivaji, Ratnasingham, and Byungjae Son. “Bifurcation and Multiplicity Results for Classes of $p,q$-Laplacian Systems”. Topological Methods in Nonlinear Analysis 48, no. 1 (April 29, 2016): 103–114. Accessed July 3, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2016.036.