@article{TM_1961_64_a5,
     author = {V. P. Il'in},
     title = {Approximation of functions in the spaces $\widetilde W_p^{(l)}(D)$ and $W_p^{(l)}(D)$},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {61--78},
     publisher = {mathdoc},
     volume = {64},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1961_64_a5/}
}