Ansari, Qamrul H., Adam Idzik, and Jen-Chih Yao. “Coincidence and Fixed Point Theorems With Applications”. Topological Methods in Nonlinear Analysis 15, no. 1 (March 1, 2000): 191–202. Accessed April 20, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2000.016.