กลิ่นเอี่ยม จักรกฤษ. “The Applications of Fixed Point Theorems for Multi-Valued Mappings on a Metric Space with a Graph”. KKU Science Journal 41, no. 3 (September 30, 2013): 657–663. accessed August 27, 2026. https://ph01.tci-thaijo.org/index.php/KKUSciJ/article/view/249156.