1. R.H. Battin, An Introduction to the Mathematics and Methods of Astrodynamics, AIAA Education Series, Vol. 1633, American Institute of Aeronautics and Astronautics, Inc., Broadway, New York, 1987.
2. Trajectory optimization using sparse sequential quadratic programming;Betts,1993
3. Using sparse nonlinear programming to compute low thrust orbit transfers;Betts;J. Astron. Sci.,1993
4. Issues in the direct transcription of optimal control problems to sparse nonlinear programs;Betts,1994
5. Optimal interplanetary orbit transfers by direct transcription;Betts;J. Astronaut. Sci.,1994