@article{ZNSL_2002_290_a0,
     author = {O. L. Vinogradov and V. V. Zhuk},
     title = {Sharp {Kolmogorov-type} inequalities for moduli of continuity and best approximations by trigonometric polynomials and splines},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--26},
     year = {2002},
     volume = {290},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2002_290_a0/}
}