@article{MZM_1977_21_4_a5,
     author = {P. Oswald},
     title = {The norm in $C$ of orthogonal projections onto subspaces of polygonal functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {495--502},
     publisher = {mathdoc},
     volume = {21},
     number = {4},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1977_21_4_a5/}
}