Odibat, Zaid, and Shaher Momani. “Applications of Variational Iteration and Homotopy Perturbation Methods to Fractional Evolution Equations”. Topological Methods in Nonlinear Analysis 31, no. 2 (June 1, 2008): 227–234. Accessed April 26, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2008.013.