@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/}
}