Yolacan, E., H. Kiziltunc, and M. Kir. “Coincidence Point Theorems for $\varphi$-$\psi$-Contraction Mappings in Metric Spaces Involving a Graph”. Carpathian Mathematical Publications 8, no. 2 (December 30, 2016): 251–262. Accessed November 21, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/1431.