1. Subbarao, P. V. and Sharma, R. K.: 1975,Astron. Astrophys. 43, 381?383.
2. Szebehely, V.: 1967a,Theory of Orbits, Academic Press.
3. Szebehely, V.: 1967b,Astron. J. 72, 7?9.
4. Wintner, A.: 1941,The Analytical Foundations of Celestial Mechanics, Princeton Univ. Press, pp. 372?373.