1. Antonov, V.A., Nikiforov, I.I., and Kholshevnikov, K.V., Elementy teorii gravitatsionnogo potentsiala i nekotorye sluchai ego yavnogo vyrazheniya (Elements of Gravitational Potential Theory and Some Cases of Its Explicit Expression), Izd. SPbGU, 2008.
2. Duboshin, G.N., Teoriya prityazheniya (Gravitation Theory), Moscow: Nauka, 1961.
3. Gordeeva, Yu.F., The Way to Take into Account the Concentrated Masses in Half-Analytical Calculation Method for Lunar Artificial Satellites Motion, in Opredelenie dvizheniya kosmicheskikh apparatov (The Way to Determine Spacecrafts Motion), Moscow: Nauka, 1975, p. 43.
4. Kondratyev, B.P., Teoriya potentsiala. Novye metody i zadachi s resheniyami (Potential Theory. New Method and Problems with Solutions), Moscow: Mir, 2007.
5. Korn, G.A. and Korn, T.N., Mathematical Handbook for Scientists and Engineers, New York, etc., 1968; Moscow: Nauka, 1970.