@article{IM2_1975_9_4_a10,
     author = {A. P. Terekhin},
     title = {A multiparameter semigroup of operators, mixed moduli and aproximation},
     journal = {Izvestiya. Mathematics},
     pages = {887--910},
     year = {1975},
     volume = {9},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1975_9_4_a10/}
}