KUMAR, Uttam and TIWARI, Sweta. Multiple solutions to Bahri-Coron problem involving fractional $p$-Laplacian in some domain with nontrivial topology. Topological Methods in Nonlinear Analysis. Online. 23 June 2023. Vol. 61, no. 2, pp. 717 - 742. [Accessed 22 July 2024]. DOI 10.12775/TMNA.2022.033.