@article{TMF_1969_1_3_a5,
     author = {A. M. Perelomov and V. S. Popov},
     title = {Group-theoretical aspects of the variable frequency oscillator problem},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {360--374},
     publisher = {mathdoc},
     volume = {1},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1969_1_3_a5/}
}