Ji, Chao, and Vicenţiu D. Rădulescu. “Ground States of Biharmonic Equations on Lattice Graphs”. Topological Methods in Nonlinear Analysis 66, no. 1 (October 1, 2025): 273–288. Accessed December 12, 2025. https://apcz.umk.pl/TMNA/article/view/65912.