@article{DE_1971_7_6_a8,
     author = {N. I. Brisch and N. J. Yurchuk},
     title = {The {Goursat} problem for abstract second order linear differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1017--1030},
     publisher = {mathdoc},
     volume = {7},
     number = {6},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_6_a8/}
}