@article{VMUMM_1990_6_a11,
     author = {A. S. Popeluhin},
     title = {On local solvability and hypoellipticity of a class of {P.D.O.} with double characteristics},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {54--56},
     year = {1990},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1990_6_a11/}
}