1. Theorie de la libration de la lune;Lagrange,1870
2. The libration of a satellite;Beletskii,1960
3. Iskusstvennye Sputniki Zemli;Beletskii,1953
4. Attitude stability of earth-pointing satellites;Kane;AIAA J.,1965
5. Non-linear resonance affecting gravity-gradient stability;Breakwell,1966