1. V. V. Dodonov, V. I. Man’ko, and O. V. Man’ko, J. Sov. Laser Res., 10, 413 (1989).
2. O. V. Manko, J. Korean Phys. Soc., 27, 1 (1994).
3. E. O. Kiktenko, A. K. Fedorov, O. V. Man’ko, and V. I. Man’ko, Phys. Rev. A, 91, 042312 (2015).
4. A. V. Dodonov, L. C. Celeri, F. Pascoal, et al., “Photon generation from vacuum in nonstationary circuit QED,” arXiv:0806.4035 (2008).
5. A. V. Dodonov, J. Phys.: Conf. Ser., 161, 012029 (2009).