%0 Journal Article %A B. A. Dubrovin %T The Kadomtsev--Petviashvili equation and the relations between the periods of holomorphic differentials on Riemann surfaces %J Izvestiya. Mathematics %D 1982 %P 285-296 %V 19 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/IM2_1982_19_2_a4/ %G en %F IM2_1982_19_2_a4