PACHPATTE, B. G. Growth estimates on certain integral inequalities in two variables involving iterated integrals. Tamkang Journal of Mathematics, [S. l.], v. 36, n. 3, p. 179-191, 2005. DOI: 10.5556/j.tkjm.36.2005.110. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/110. Acesso em: 3 dec. 2021.