RUS, Ioan A. Some variants of contraction principle, generalizations and applications: Dedicated to Professor Gheorghe Coman on the occasion of his 80th anniversary. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 61, n. 3, p. 343–358, 2016. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/5585. Acesso em: 5 feb. 2025.