@article{TM_1987_180_a89,
     author = {N. E. Lushpai and I. L. Zaichenko},
     title = {Extremal numerical integration formulas for classes of differentiable periodic functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {152--154},
     year = {1987},
     volume = {180},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1987_180_a89/}
}