@article{MZM_1991_49_5_a2,
     author = {K. Kh. Boimatov},
     title = {Spectral projections of hypoelliptic operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {16--25},
     year = {1991},
     volume = {49},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1991_49_5_a2/}
}