@article{TIMM_1998_5_a12,
     author = {S. I. Novikov},
     title = {On solvability of a~spectral boundary value problem},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {174--182},
     year = {1998},
     volume = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_1998_5_a12/}
}