@article{DAN_1985_280_2_a1,
     author = {Yu. A. Brudnyi and P. A. Shvartsman},
     title = {A linear extension operator for a space of smooth functions defined on a closed subset in $\mathbf{R}^n$},
     journal = {Doklady Akademii Nauk},
     pages = {268--272},
     publisher = {mathdoc},
     volume = {280},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1985_280_2_a1/}
}