LI, W.-R.; CHENG, S. S. Discrete Ou-Iang type inequalities. Tamkang Journal of Mathematics, [S. l.], v. 31, n. 4, p. 305–310, 2000. DOI: 10.5556/j.tkjm.31.2000.388. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/388. Acesso em: 27 apr. 2024.