@article{TMF_2019_198_3_a4,
     author = {Sh. M. Nagiyev and A. I. Akhmedov},
     title = {Time evolution of quadratic quantum systems: {Evolution} operators, propagators, and invariants},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {451--472},
     publisher = {mathdoc},
     volume = {198},
     number = {3},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2019_198_3_a4/}
}