1. Burša, M.: 1983, Bull. Astron. Inst. Czechosl. 34, 74.
2. Gaposċhkin, E. M.: 1973, ‘Smithsonian Standard Earth’ (III) SAO Spec. Repr. 353.
3. Jeffreys, H.: 1962, ‘The Earth’ (4th edition) Cambridge Univ. Press, Cambridge.
4. Kaula, W. M.: 1966, ‘Theory of Satellite Geodesy’, Blaisdell Publ. Co., Waltham-Toronto-London.
5. Kozai, Y. and Kinoshita, H.: 1973, Celes. Mech. 7, 356.