@article{VMUMM_1987_4_a2,
     author = {\`E. M. Galeev},
     title = {Linear widths of classes of periodic functions of several variables},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {13--16},
     year = {1987},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1987_4_a2/}
}