%0 Journal Article %A V. G. Krotov %T Differential properties on the boundary of functions that are holomorphic in the unit ball in~$C^N$ %J Matematičeskie zametki %D 1989 %P 51-59 %V 45 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/MZM_1989_45_2_a5/ %G ru %F MZM_1989_45_2_a5