@article{DAN_1967_176_6_a3,
     author = {B. A. Vostretsov and A. V. Ignat'eva},
     title = {The existence in the $L_p$ metric of the best approximation of functions by sums of a finite number of plane waves of given directions},
     journal = {Doklady Akademii Nauk},
     pages = {1225--1228},
     publisher = {mathdoc},
     volume = {176},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_176_6_a3/}
}