Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1987_42_1_a2, author = {A. I. Stepanets}, title = {Best approximations of infinitely differentiable functions in the space~$L_s$}, journal = {Matemati\v{c}eskie zametki}, pages = {21--32}, publisher = {mathdoc}, volume = {42}, number = {1}, year = {1987}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1987_42_1_a2/} }
A. I. Stepanets. Best approximations of infinitely differentiable functions in the space~$L_s$. Matematičeskie zametki, Tome 42 (1987) no. 1, pp. 21-32. http://geodesic.mathdoc.fr/item/MZM_1987_42_1_a2/