@article{DAN_1972_202_2_a1,
     author = {V. I. Burenkov},
     title = {On approximation of functions in {Sobolev} spaces by finite functions on an arbitrary open set},
     journal = {Doklady Akademii Nauk},
     pages = {259--262},
     publisher = {mathdoc},
     volume = {202},
     number = {2},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_202_2_a1/}
}