V. Naga Raju, and G. Upender Reddy. “Common Fixed Point Theorem for Four Self Maps of \(S\)-Metric Spaces by Employing Compatibility of type(R)”. Malaya Journal of Matematik 8, no. 04 (October 1, 2020): 1735–1742. Accessed July 16, 2024. https://www.malayajournal.org/index.php/mjm/article/view/1738.