1. M. F. Subbotin, Introduction to Theoretical Astronomy (Nauka, Moscow, 1968) [in Russian].
2. K. Charlier, Die Mechanik des Himmels (Veit, Leipzig, 1927; Nauka, Moscow, 1966).
3. K. V. Kholshevnikov and V. B. Titov, The Two-Body Problem. A Tutorial (SPb. Gos. Univ., St.-Petersburg, 2007) [in Russian].