@article{MP_1957_2_1_a20,
     author = {A. P. Norden},
     title = {{\CYRK}{\cyra}{\cyrz}{\cyra}{\cyrn}{\cyrs}{\cyrk}{\cyro}{\cyre} {\cyrf}{\cyri}{\cyrz}{\cyri}{\cyrk}{\cyro}-{\cyrm}{\cyra}{\cyrt}{\cyre}{\cyrm}{\cyra}{\cyrt}{\cyri}{\cyrch}{\cyre}{\cyrs}{\cyrk}{\cyro}{\cyre} {\cyro}{\cyrb}{\cyrshch}{\cyre}{\cyrs}{\cyrt}{\cyrv}{\cyro}},
     journal = {Matematicheskoe Prosveshchenie},
     pages = {179--181},
     year = {1957},
     volume = {Ser. 2, 1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MP_1957_2_1_a20/}
}