%0 Journal Article %A T. V. Kirsanova %T First-order semitangent structures %J Trudy Geometricheskogo Seminara %D 1984 %P 41-47 %V 16 %U http://geodesic.mathdoc.fr/item/KUTGS_1984_16_a5/ %G ru %F KUTGS_1984_16_a5