Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1967_2_4_a6, author = {S. A. Freidkin}, title = {The spectrum of a singular operator}, journal = {Matemati\v{c}eskie zametki}, pages = {379--384}, publisher = {mathdoc}, volume = {2}, number = {4}, year = {1967}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1967_2_4_a6/} }
S. A. Freidkin. The spectrum of a singular operator. Matematičeskie zametki, Tome 2 (1967) no. 4, pp. 379-384. http://geodesic.mathdoc.fr/item/MZM_1967_2_4_a6/