Papageorgiou, Nikolaos S., and Vicenţiu D. Rădulescu. “Positive Solutions for Parametric Semilinear Robin Problems With Indefinite and Unbounded Potential”. MATHEMATICA SCANDINAVICA 121, no. 2 (October 22, 2017): 263–292. Accessed April 25, 2024. https://www.mscand.dk/article/view/96696.