@article{VMUMM_1987_2_a21,
     author = {N. N. Yakovlev},
     title = {On the spectrum of the {Schr\"odinger} operator with small periodic potential in dimensions two and three},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {77--79},
     publisher = {mathdoc},
     number = {2},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1987_2_a21/}
}