@article{TM_1972_117_a9,
     author = {I. A. Kipriyanov},
     title = {Asymptotic distribution of eigenvalues and eigenfunctions of a certain class of singular elliptic operators},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {159--179},
     year = {1972},
     volume = {117},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1972_117_a9/}
}