K. Boshkayev, Z. Kalymova, N. Abdualiyeva, Z. Brisheva, and Taukenova А., “Investigation of a test particle motion in the equatorial plane of the axially symmetric gravitational field in terms of the adiabatic theory”, Rec.Contr.Phys., vol. 2018, no. 1, pp. 67–80, Mar. 2018.