M. Houas, M. Benbachir, and Z. Dahmani. “Some Results for a Four-Point Boundary Value Problems for a Coupled System Involving Caputo Derivatives”. Malaya Journal of Matematik 3, no. 01 (January 1, 2015): 30–44. Accessed November 24, 2024. https://www.malayajournal.org/index.php/mjm/article/view/449.