MASSALITINA, E. V. On the Perov Integro-Summable Inequality for Functions of Two Variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 11, p. 1569–1576, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3866. Acesso em: 6 dec. 2025.