@article{CMUC_2003_44_4_a7,
     author = {Hakobyan, G. O. and Margaryan, V. N.},
     title = {Gevrey hypoellipticity for a class of degenerated quasi-elliptic operators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {637--644},
     year = {2003},
     volume = {44},
     number = {4},
     mrnumber = {2062880},
     zbl = {1098.35058},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2003_44_4_a7/}
}