@article{DAN_1983_271_6_a4,
     author = {B. K. Kokebayev and M. Otelbaev and A. N. Shynybekov},
     title = {On questions of extension and restriction of operators},
     journal = {Doklady Akademii Nauk},
     pages = {1307--1310},
     publisher = {mathdoc},
     volume = {271},
     number = {6},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1983_271_6_a4/}
}