%0 Journal Article %A Z. D. Usmanov %T On a problem concerning the deformation of a surface with a flat point %J Sbornik. Mathematics %D 1972 %P 61-81 %V 18 %N 1 %U http://geodesic.mathdoc.fr/item/SM_1972_18_1_a3/ %G en %F SM_1972_18_1_a3