1. M-hyponormal operators;Arora;Yokohama Math. J.,1980
2. An extension of Weyl's theorem to a class of not necessarily normal operators;Berberian;Michigan Math. J.,1969
3. The Weyl spectrum of an operator;Berberian;Indiana Univ. Math. J.,1970
4. M. Cho, and, K. Tanahashi, Spectral properties of log-hyponormal operators, preprint.
5. M. Cho, I. S. Hwang, and, J. I. Lee, On the spectral properties of log-hyponormal operators, preprint.