@article{DAN_1980_252_2_a5,
     author = {A. Dzhuraev},
     title = {Some problems for systems of first order partial differential equations of composite type in three-dimensional space},
     journal = {Doklady Akademii Nauk},
     pages = {280--286},
     publisher = {mathdoc},
     volume = {252},
     number = {2},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1980_252_2_a5/}
}