%0 Journal Article %A L. N. Ivanovsky %T Proof of a hypothesis advanced by P.\,S.~Alexandrov %J Doklady Akademii Nauk %D 1958 %P 785-786 %V 123 %N 5 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1958_123_5_a3/ %G ru %F DAN_1958_123_5_a3