1. Yu. G. Ignat’ev, Space, Time and Fund. Interact., No. 3, 37–47 (2016); arXiv:1609.00745 [gr-qc].
2. Yu. G. Ignat’ev, Space, Time and Fund. Interact., No. 3, 6–36 (2016); arXiv:1609.08851[gr-qc].
3. Yu. G. Ignat’ev, Grav. Cosmol., 23, No. 2, 131–141 (2017).
4. Yu. G. Ignat’ev and A. A. Agathonov, Space, Time and Fund. Interact., No. 1, 46–65 (2017).
5. Yu. G. Ignat’ev and A. R. Samigullina, Space, Time and Fund. Interact., No. 4, 147–148 (2016).