@article{TMF_1975_23_3_a14, author = {A. A. Arsen'ev}, title = {Note on estimating the width of lower energy bands in a periodic potential}, journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika}, pages = {418--420}, publisher = {mathdoc}, volume = {23}, number = {3}, year = {1975}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/TMF_1975_23_3_a14/} }