@article{MT_1996_31_a4,
     author = {A. V. Greshnov},
     title = {Extension of differentiable functions beyond the boundary of the domain on {Carnot} groups},
     journal = {Matemati\v{c}eskie trudy},
     pages = {161--186},
     publisher = {mathdoc},
     volume = {31},
     year = {1996},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1996_31_a4/}
}