1. Arenstorf, R. F.: 1967, in J. K. Hale and J. P. Lasalle (eds.),Differential Equations and Dynamical Problems, Academic Press, pp. 55?68.
2. Boggs, D. H.: 1972,AIAA J. 10, 675?678.
3. Broucke, R. A.: 1968, NASA-JPL Technical Report, 32?1168.
4. Broucke, R. A.: 1969,AIAA J. 7, 1003?1009.
5. Broucke, R. A.: 1972,J. Astron. Sci. 19, 417?432.