@article{IVM_1967_6_a13,
     author = {V. M. Finkel'shtein},
     title = {Certain classes of four-parameter direction fields connected with a~non-holonomic surface orthogonal to an arbitrary congruence},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {109--116},
     publisher = {mathdoc},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1967_6_a13/}
}