PACHPATTE, B. G. Inequalities of Opial type in three independent variables. Tamkang Journal of Mathematics, [S. l.], v. 35, n. 2, p. 145–158, 2004. DOI: 10.5556/j.tkjm.35.2004.216. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/216. Acesso em: 28 mar. 2024.