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@article{IVM_1975_9_a4, author = {A. D. Ivanov}, title = {Four-dimensional {Bol} webs of elliptic or hyperbolic type}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {25--34}, publisher = {mathdoc}, number = {9}, year = {1975}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1975_9_a4/} }
A. D. Ivanov. Four-dimensional Bol webs of elliptic or hyperbolic type. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 9 (1975), pp. 25-34. http://geodesic.mathdoc.fr/item/IVM_1975_9_a4/