@article{1102866809,
author = {Shiu, Elias S. W.},
title = {Commutators and numerical ranges of powers of operators.},
journal = {Pacific J. Math.},
volume = {67},
number = {2},
year = {1976},
pages = { 517-523},
language = {en},
url = {http://dml.mathdoc.fr/item/1102866809}
}
Shiu, Elias S. W. Commutators and numerical ranges of powers of operators.. Pacific J. Math., Tome 67 (1976) no. 2, pp. 517-523. http://gdmltest.u-ga.fr/item/1102866809/