BONY, J.-M.; COLOMBINI, F.; PERNAZZA, L. On square roots of class C^m of nonnegative functions of one variable. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, [S. l.], v. 9, n. 3, p. 635-644, 2010. DOI: 10.2422/2036-2145.2010.3.08. Disponível em: http://20.103.181.36/index.php/annaliscienze/article/view/216. Acesso em: 28 may. 2025.