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@article{IVM_1972_12_a10, author = {Ya. L. Shapiro}, title = {The two-sheeted structure on a~reducible {Riemannian} manifold}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {102--110}, publisher = {mathdoc}, number = {12}, year = {1972}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1972_12_a10/} }
Ya. L. Shapiro. The two-sheeted structure on a~reducible Riemannian manifold. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 12 (1972), pp. 102-110. http://geodesic.mathdoc.fr/item/IVM_1972_12_a10/