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@article{IVM_1994_3_a16, author = {N. I. Guseva}, title = {Lines of pseudofoci and the focal curve of the distribution $\Delta_2$ in $E_4$}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {84--87}, publisher = {mathdoc}, number = {3}, year = {1994}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1994_3_a16/} }
N. I. Guseva. Lines of pseudofoci and the focal curve of the distribution $\Delta_2$ in $E_4$. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 3 (1994), pp. 84-87. http://geodesic.mathdoc.fr/item/IVM_1994_3_a16/