@article{DAN_1957_115_2_a10,
     author = {P. E. Sobolevskii},
     title = {Approximate methods of solving differential equations in {Banach} space},
     journal = {Doklady Akademii Nauk},
     pages = {240--243},
     publisher = {mathdoc},
     volume = {115},
     number = {2},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_115_2_a10/}
}