Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1979_25_3_a10, author = {A. N. Kochubei}, title = {Symmetric operators and nonclassical spectral problems}, journal = {Matemati\v{c}eskie zametki}, pages = {425--434}, publisher = {mathdoc}, volume = {25}, number = {3}, year = {1979}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1979_25_3_a10/} }
A. N. Kochubei. Symmetric operators and nonclassical spectral problems. Matematičeskie zametki, Tome 25 (1979) no. 3, pp. 425-434. http://geodesic.mathdoc.fr/item/MZM_1979_25_3_a10/