@article{TIMM_2015_21_4_a22,
     author = {S. A. Stasyuk},
     title = {Approximation of certain smoothness classes of periodic functions of several variables by polynomials with regard to the tensor {Haar} system},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {251--260},
     publisher = {mathdoc},
     volume = {21},
     number = {4},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_2015_21_4_a22/}
}