@article{DE_1977_13_2_a11,
     author = {V. K. Romanko},
     title = {Unique solvability of boundary value problems for certain operator-differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {324--335},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_2_a11/}
}