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@article{MZM_1981_30_5_a5, author = {M. G. Gimadislamov}, title = {Criteria for the discreteness of the spectrum of a hypoelliptic operator}, journal = {Matemati\v{c}eskie zametki}, pages = {685--693}, publisher = {mathdoc}, volume = {30}, number = {5}, year = {1981}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1981_30_5_a5/} }
M. G. Gimadislamov. Criteria for the discreteness of the spectrum of a hypoelliptic operator. Matematičeskie zametki, Tome 30 (1981) no. 5, pp. 685-693. http://geodesic.mathdoc.fr/item/MZM_1981_30_5_a5/