1. AAS Science and Technology Series;S. P. Altman,1966
2. Acceleration Hodograph Analysis Techniques for Powered Orbital Trajectories, NASA Contractor Report CR-61615, June 1967.
3. Altman, S. P. and Pistiner, J. S.: 1968, ?Application of State Space Transformation Theory to Orbit Determination and Prediction?, AAS Paper No. 68-111, AAS/AIAA Astrodynamics Specialist Conference, Jackson, Wyoming, September 3?5.
4. Tapley, B. D., Szebehely, V., and Lewallen, J. M.: 1968, ?Trajectory Optimization Using Regularized Variables?, AAS Paper No. 68-099, AAS/AIAA Astrodynamics Specialist Conference, Jackson, Wyoming, September 3?5.
5. Lewallen, J. M., Schwausch, O. A., and Tapley, B. D.: 1969, ?Coordinate System Influence on the Regularized Trajectory Optimization Problem?, AIAA Paper No. 69-903, AIAA/AAS Astrodynamics Conference, Princeton, New Jersey, August 20?22.