Webb, J. R. L. and Lan, K. Q. (2006) “Eigenvalue criteria for existence of multiple positive solutions of nonlinear boundary value problems of local and nonlocal type”, Topological Methods in Nonlinear Analysis, 27(1), pp. 91–115. Available at: https://apcz.umk.pl/TMNA/article/view/TMNA.2006.003 (Accessed: 1 February 2023).