@article{TMF_1971_9_1_a10,
     author = {Yu. A. Nepomnyashchii and A. A. Nepomnyashchii},
     title = {Collective spectrum of coherent crystals},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {137--149},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1971_9_1_a10/}
}