@article{INTG_1969_2_a1,
     author = {V. I. Bliznikas},
     title = {The geometry of systems of first order partial differential equations},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {33--53},
     publisher = {mathdoc},
     volume = {2},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1969_2_a1/}
}