@article{MZM_1998_64_3_a0,
     author = {V. V. Arestov},
     title = {The best approximation to a class of functions of several variables by another class and related extremum problems},
     journal = {Matemati\v{c}eskie zametki},
     pages = {323--340},
     publisher = {mathdoc},
     volume = {64},
     number = {3},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1998_64_3_a0/}
}