Common fixed points for four self-maps in cone metric spaces. JOURNAL OF ADVANCES IN MATHEMATICS, [S. l.], v. 5, n. 1, p. 607–612, 2013. DOI: 10.24297/jam.v5i1.3674. Disponível em: https://www.rajpub.com/index.php/jam/article/view/3674. Acesso em: 4 jul. 2025.