@article{RM_1981_36_5_a7,
     author = {V. A. Chulaevskii},
     title = {On~perturbations of {a~Schr\"odinger} operator with periodic potential},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {143--144},
     publisher = {mathdoc},
     volume = {36},
     number = {5},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1981_36_5_a7/}
}