@article{DAN_1972_205_2_a1,
     author = {M. Sh. Birman and M. Z. Solomyak},
     title = {Spectral asymptotics of nonsmooth elliptic operators},
     journal = {Doklady Akademii Nauk},
     pages = {267--270},
     publisher = {mathdoc},
     volume = {205},
     number = {2},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_205_2_a1/}
}