@article{MMO_1989_52_a1,
     author = {S. Z. Levendorskiǐ},
     title = {The asymptotics of the spectrum of operators that are elliptic in the sense of {Douglis--Nirenberg}},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {34--57},
     publisher = {mathdoc},
     volume = {52},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1989_52_a1/}
}