RICCERI, Biagio. A class of functionals possessing multiple global minima. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 66, n. 1, p. 75–84, 2022. DOI: 10.24193/subbmath.2021.1.06. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1247. Acesso em: 10 feb. 2025.