@article{IVM_1971_1_a1,
     author = {M. T. Vinogradova and V. V. Smirnova},
     title = {Unilateraly stratifiable pairs of families of $(2-2)$-planes in $E_5$},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {9--20},
     publisher = {mathdoc},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1971_1_a1/}
}