@article{SJVM_2012_15_3_a0,
     author = {A. B. Andreev and M. R. Racheva},
     title = {Lower bounds for eigenvalues and postprocessing by an integral type nonconforming {FEM}},
     journal = {Sibirskij \v{z}urnal vy\v{c}islitelʹnoj matematiki},
     pages = {235--249},
     publisher = {mathdoc},
     volume = {15},
     number = {3},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJVM_2012_15_3_a0/}
}