@article{IVM_1963_4_a12,
     author = {G. N. Makeev},
     title = {Focal $\Theta$ pairs},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {92--98},
     publisher = {mathdoc},
     number = {4},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1963_4_a12/}
}