Cassani, Daniele, João Marcos do Ó, and Jianjun Zhang. 2016. “Multi-Bump Solutions for Singularly Perturbed Schrödinger Equations in $\mathbb{R}^2$ With General Nonlinearities”. Topological Methods in Nonlinear Analysis 49 (1):205-31. https://apcz.umk.pl/TMNA/article/view/TMNA.2016.074.