@article{ZVMMF_1979_19_4_a12,
     author = {L. T. Poznyak},
     title = {A~method of~estimating lower bounds for eigenvalues of~differential operators by~the~method of~fictitious domains},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {921--936},
     publisher = {mathdoc},
     volume = {19},
     number = {4},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1979_19_4_a12/}
}