1. Baumgarte, J.: 1972,Celes. Mech. 5, 490.
2. Baumgarte, J. and Stiefel, E.: 1974,Lecture Notes in Mathematics, Vol. 362, Springer-Verlag, Berlin, p. 207.
3. Bettis, D. G.: 1972, unpublished.
4. CIRA: 1965,COSPAR International Reference Atmosphere, North-Holland Publishing Company, Amsterdam.
5. Fehlberg, E.: 1968, NASA TR R-287.