Faraci, F., and A. Iannizzotto. “On the Topological Dimension of the Solution Set of a Class of Nonlocal Elliptic Problems”. Topological Methods in Nonlinear Analysis, vol. 42, no. 1, Sept. 2013, pp. 1-8, https://apcz.umk.pl/TMNA/article/view/TMNA.2013.022.