@article{IIMI_2013_1_a2,
     author = {L. I. Danilov},
     title = {On the spectrum of a two-dimensional generalized periodic {Schr\"odinger} operator},
     journal = {Izvestiya Instituta Matematiki i Informatiki Udmurtskogo Gosudarstvennogo Universiteta},
     pages = {78--95},
     year = {2013},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IIMI_2013_1_a2/}
}