DUGGAL, B. P. A Note on an Inequality of Schur. The Journal of the Indian Mathematical Society, [S. l.], v. 39, n. 1-4, p. 331–336, 1975. Disponível em: http://informaticsjournals.com/index.php/jims/article/view/16662. Acesso em: 2 may. 2024.