@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/}
}