IMDAD, M.; KUMAR, S. Common Fixed Point Theorems for Four Nonself Mappings. The Journal of the Indian Mathematical Society, [S. l.], v. 70, n. 1-4, p. 97–109, 2003. Disponível em: https://www.informaticsjournals.com/index.php/jims/article/view/21912. Acesso em: 29 apr. 2024.