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@article{DAN_1976_226_2_a0, author = {V. G. Boltyanskii}, title = {Helly's theorem for $H$-convex sets}, journal = {Doklady Akademii Nauk}, pages = {249--252}, publisher = {mathdoc}, volume = {226}, number = {2}, year = {1976}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1976_226_2_a0/} }
V. G. Boltyanskii. Helly's theorem for $H$-convex sets. Doklady Akademii Nauk, Tome 226 (1976) no. 2, pp. 249-252. http://geodesic.mathdoc.fr/item/DAN_1976_226_2_a0/