SHAH, N. C.; SHETH, I. H. Some Results on Quasi-Hyponormal Operators. The Journal of the Indian Mathematical Society, [S. l.], v. 39, n. 1-4, p. 285–291, 1975. Disponível em: https://informaticsjournals.com/index.php/jims/article/view/16653. Acesso em: 3 may. 2024.