@article{1102817372, author = {Lutz, Dieter}, title = {A perturbation theorem for spectral operators.}, journal = {Pacific J. Math.}, volume = {73}, number = {2}, year = {1977}, pages = { 127-134}, language = {en}, url = {http://dml.mathdoc.fr/item/1102817372} }
Lutz, Dieter. A perturbation theorem for spectral operators.. Pacific J. Math., Tome 73 (1977) no. 2, pp. 127-134. http://gdmltest.u-ga.fr/item/1102817372/