1. Yu. G. Ignat’ev and I. A. Kokh, Grav. Cosmol. (this issue).
2. Yu. G. Ignat’ev and A. R. Samigullina, Space, Time and Fundamental Interections. 3(20), 28 (2017).
3. Yu. G. Ignat’ev, A. A. Agathonov, and D. Ignatyev, Grav. Cosmol. 24, 1 (2018).
4. Yu. G. Ignat’ev, Space, Time and Fundamental Interections 1(1), 79 (2012).
5. Yu. G. Ignat’ev and M. L. Mikhailov, Space, Time and Fundamental Interections 4(13), 75 (2015).