@article{DAN_1964_155_3_a1,
     author = {N. G. Askerov and S. G. Krein and G. I. Laptev},
     title = {On a class of non-selfadjoint boundary-value problems},
     journal = {Doklady Akademii Nauk},
     pages = {499--502},
     publisher = {mathdoc},
     volume = {155},
     number = {3},
     year = {1964},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1964_155_3_a1/}
}