Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MAT_1974_18_1_a4, author = {J. G. Stampfli}, title = {Hyponormal operators and spectral density}, journal = {Matematika}, pages = {95--101}, publisher = {mathdoc}, volume = {18}, number = {1}, year = {1974}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MAT_1974_18_1_a4/} }
J. G. Stampfli. Hyponormal operators and spectral density. Matematika, Tome 18 (1974) no. 1, pp. 95-101. http://geodesic.mathdoc.fr/item/MAT_1974_18_1_a4/