@article{TMF_2010_162_3_a4,
     author = {I. S. Lobanov and V. Yu. Lotoreichik and I. Yu. Popov},
     title = {Lower bound on the~spectrum of the~two-dimensional {Schr\"odinger} operator with a~$\delta$-perturbation on a~curve},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {397--407},
     publisher = {mathdoc},
     volume = {162},
     number = {3},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2010_162_3_a4/}
}