1. G. Beutler, Methods of Celestial Mechanics, Vol. 1: Physical, Mathematical, and Numerical Principles (Springer, New York, 2005).
2. S. V. Ershkov, Adv. Astron. 2015, 615029 (2015).
3. S. V. Ershkov and D. Leshchenko, Astrophys. Space Sci. 364 (11), 207 (2019).
4. A. Abozaid, H. H. Selim, K. A. Gadallah, I. A. Hassan, and E. I. Abouelmagd, Appl. Math. Nonlin. Sci. 5, 157 (2020).
5. R. K. Sharma and P. V. S. Rao, Celest. Mech. 13, 137 (1976).