@article{DAN_1972_207_5_a6,
     author = {G. A. Kolupanova},
     title = {On a differential equation of hyperbolic type in {Banach} space},
     journal = {Doklady Akademii Nauk},
     pages = {1044--1047},
     publisher = {mathdoc},
     volume = {207},
     number = {5},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_207_5_a6/}
}