@article{DE_1980_16_1_a14,
     author = {V. K. Romanko},
     title = {The conjugation problem for operator-differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {124--134},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_1_a14/}
}