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@article{DAN_1968_180_5_a23, author = {M. Sh. Yakupov}, title = {Einstein's spaces of the second order of immersion}, journal = {Doklady Akademii Nauk}, pages = {1096--1098}, publisher = {mathdoc}, volume = {180}, number = {5}, year = {1968}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1968_180_5_a23/} }
M. Sh. Yakupov. Einstein's spaces of the second order of immersion. Doklady Akademii Nauk, Tome 180 (1968) no. 5, pp. 1096-1098. http://geodesic.mathdoc.fr/item/DAN_1968_180_5_a23/