@article{SJVM_2001_4_1_a6,
     author = {S. B. Sorokin},
     title = {The substantiation of the method of two-sided approximations for eigenvalues of the second-order elliptic operator},
     journal = {Sibirskij \v{z}urnal vy\v{c}islitelʹnoj matematiki},
     pages = {61--84},
     publisher = {mathdoc},
     volume = {4},
     number = {1},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJVM_2001_4_1_a6/}
}