Dynamics of a two-level system and estimate of the relaxation time

@article{Bogolyubov1982DynamicsOA,
  title={Dynamics of a two-level system and estimate of the relaxation time},
  author={N. N. Jr Bogolyubov and Fam Le Kien and A. S. Shumovskiĭ},
  journal={Theoretical and Mathematical Physics},
  year={1982},
  volume={53},
  pages={1014-1018}
}