Sumalai, P., P. Kumam, C. Khaofong, and J. Martinez-Moreno. “New Common Coupled Coincidence Point Theorems for Generalized Weakly Contraction Mappings With Applications to Dynamic Programming”. Communications in Mathematics and Applications, vol. 9, no. 1, Apr. 2018, pp. 1-14, doi:10.26713/cma.v9i1.666.