@article{1250126129,
author = {Conway, J.B. and Szymanski, W.},
title = {Linear combinations of hypernormal operators},
journal = {Rocky Mountain J. Math.},
volume = {18},
number = {4},
year = {1988},
pages = { 695-706},
language = {en},
url = {http://dml.mathdoc.fr/item/1250126129}
}
Conway, J.B.; Szymanski, W. Linear combinations of hypernormal operators. Rocky Mountain J. Math., Tome 18 (1988) no. 4, pp. 695-706. http://gdmltest.u-ga.fr/item/1250126129/