PETRU, T. P.; BORICEANU, M. Fixed point results for generalized $\varphi$-contraction on a set with two metrics. Topological Methods in Nonlinear Analysis, [S. l.], v. 33, n. 2, p. 315–326, 2009. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2009.021. Acesso em: 3 jul. 2024.