@article{TMF_1990_85_1_a2,
     author = {A. S. Kopets},
     title = {Quasiregular solutions for systems of~hypoelliptic differential equations},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {25--31},
     publisher = {mathdoc},
     volume = {85},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1990_85_1_a2/}
}