@article{MZM_1969_6_4_a12,
     author = {N. E. Lushpai},
     title = {Best quadrature formulas on classes of differentiable periodic functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {475--481},
     publisher = {mathdoc},
     volume = {6},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1969_6_4_a12/}
}