1. Ahern, J.E. (1983) Briefing for Robert Williams on Second Law Thermodynamics, DARPA Copper Canyon manager, Washington, DC.
2. Ahern, J.E. (1992) ‘Thermal Management of Air-Breathing Propulsion Systems’, AIAA 92-0514, 30th Aerospace Sciences Meeting, Reno, Nevada, January 1992.
3. Anfimov, N.A. (1997) ‘In Searching for an Optimal Concept of Future Russian Reusable Space Transportation System’, Proceedings of the International Workshop on Spaceplane/RLV Technology Demonstrators, March 1997, Tokyo Japan, pp. 67–96.
4. Anon. HyFAC (1970) ‘Hypersonic Research Facilities Study, Prepared under NASA contract NAS2-5458. NASA CR 114324, October 1970.
5. Anon. BAC (1991) ‘An-225/Interim HOTOL Launch System Study’, British Aircraft Company Presentation to the European Space Agency, Paris, 21 June 1991.