@article{AA_2003_15_2_a2,
     author = {T. A. Suslina},
     title = {Descrete spectrum of the two-dimensional periodic second order elliptic operator perturbed by a~decaying potential. {II.~Internal} gaps},
     journal = {Algebra i analiz},
     pages = {128--189},
     publisher = {mathdoc},
     volume = {15},
     number = {2},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2003_15_2_a2/}
}