@article{SM_1987_57_1_a4,
     author = {S. Z. Levendorskii},
     title = {Asymptotics of the spectrum of problems with constraints},
     journal = {Sbornik. Mathematics},
     pages = {77--95},
     publisher = {mathdoc},
     volume = {57},
     number = {1},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_57_1_a4/}
}