@article{DAN_1971_197_2_a3,
     author = {I. M. Koval'chik},
     title = {On systems of equations in a function space},
     journal = {Doklady Akademii Nauk},
     pages = {265--267},
     publisher = {mathdoc},
     volume = {197},
     number = {2},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_197_2_a3/}
}