@article{ZNSL_2007_350_a4,
     author = {A. S. Zhuk},
     title = {Approximating periodic functions in {H\"older} type metrics by singular integrals with positive kernels},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {52--69},
     year = {2007},
     volume = {350},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2007_350_a4/}
}