@article{FAA_1981_15_1_a14,
     author = {A. V. Sobolev and V. A. Khatskevich},
     title = {Definite invariant subspaces and the structure of the spectrum of a focusing plus-operator},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {84--85},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1981_15_1_a14/}
}