Naidu, S. V. R. “Fixed Point Theorems for Four Self-Maps on a Metric Space by Altering Distances”. The Journal of the Indian Mathematical Society 71, no. 1-4 (December 1, 2004): 153–173. Accessed November 7, 2024. https://informaticsjournals.co.in/index.php/jims/article/view/22040.