URS, Cristina. Fixed point theorems for a system of operator equations with applications. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 61, n. 1, p. 87–94, 2016. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/5520. Acesso em: 19 apr. 2025.