Kefi, K. “Multiple Solutions for a $p(x)$-Laplacian-Like Problem under Neumann Boundary Condition”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 76, no. 8, Sept. 2024, pp. 1158-67,
https://doi.org/10.3842/umzh.v76i8.7575
.