@article{DAN_1987_293_6_a2,
     author = {S. Z. Levendorskii},
     title = {On generalizations of the {Weyl} formula for degenerate operators},
     journal = {Doklady Akademii Nauk},
     pages = {1297--1301},
     publisher = {mathdoc},
     volume = {293},
     number = {6},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_293_6_a2/}
}