@article{CMUC_1972__13_1_a5,
     author = {Naumann, Joachim},
     title = {A characterization of the eigenvalues of a completely continuous selfadjoint operator},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {63--78},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1972},
     mrnumber = {0305207},
     zbl = {0232.47027},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1972__13_1_a5/}
}