@article{MT_1995_29_a1,
     author = {S. K. Vodopyanov and V. M. Chernikov},
     title = {Sobolev spaces and hypoelliptic equations},
     journal = {Matemati\v{c}eskie trudy},
     pages = {7--62},
     publisher = {mathdoc},
     volume = {29},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1995_29_a1/}
}