Mbehou, M., and E.F. Doungmo Goufo. “The Crank-Nicolson-Galerkin FEM for a Nonlocal Parabolic System”. Italian Journal of Pure and Applied Mathematics, vol. 42, July 2019, pp. 635-51, https://journals.uniurb.it/index.php/ijpam/article/view/7202.