@article{VMUMM_1986_1_a19,
     author = {V. M. Karnaukhov},
     title = {Sufficient conditions for {Gevrey} hypoellipticity of a class of second- order differential operators},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {68--70},
     publisher = {mathdoc},
     number = {1},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1986_1_a19/}
}