@article{MZM_1970_7_1_a4,
     author = {Yu. N. Subbotin},
     title = {Diameter of class $W^rL$ in $L(0,2\pi)$ and spline function approximation},
     journal = {Matemati\v{c}eskie zametki},
     pages = {43--52},
     publisher = {mathdoc},
     volume = {7},
     number = {1},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1970_7_1_a4/}
}