@article{IM2_2000_64_1_a3,
     author = {N. N. Pustovoitov},
     title = {The orthoprojection widths of some classes of periodic functions of two variables with a~given majorant of the mixed moduli of continuity},
     journal = {Izvestiya. Mathematics },
     pages = {121--141},
     publisher = {mathdoc},
     volume = {64},
     number = {1},
     year = {2000},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2000_64_1_a3/}
}