K. P. R. SASTRY; K. K. M. SARMA; P. KRISHNA KUMARI; SUNITHA CHOUDARI. Fixed Point Theorems for $\psi$-contractions in S-metric Spaces and KKS-metric Spaces. International Journal of Mathematics And its Applications, [S. l.], v. 5, n. 4 - E, p. 619–632, 2017. Disponível em: http://ijmaa.in/index.php/ijmaa/article/view/1318. Acesso em: 20 may. 2024.