1. Schöttle, U. M., Flug-und Antriebsoptimierung luftatmender aerodynamischer Raumfahrtträger, Dissertation, University of Stuttgart, 1988 (in German).
2. Landiech, P., Aumasson, C., and Drox, Y., Airbreathing Launchers Trajectory Optimization, Preprint, 40th IAF Congress, Malaga, Spain, 1989.
3. Jänsch, C., Schnepper, K., and Well, K. H., Trajectory Optimization of a Transatmospheric Vehicle, Proceedings of the American Control Conference, Boston, Massachusetts, pp. 2232–2237, 1991.
4. Jänsch, C., Schnepper, K., and Well, K. H., Ascent and Descent Trajectory Optimization for Ariane V/Hermes, Preprint, 75th Symposium of the AGARD Flight Mechanics Panel on Space Vehicle Flight Mechanics, Luxembourg City, Luxembourg, 1989.
5. Cliff, E., Schnepper, K., and Well, K. H., Performance Analysis of a Transatmospheric Vehicle, Paper AIAA-90–5257, 2nd AIAA Aerospace Plane Conference, Orlando, Florida, 1990.