Eric Berger
United States. General Accounting Office
J. I. Orlando
Michael Dahl
Steven J. Isakowitz
Michael Lennick
Patrick J. G. Stiennon
Linda M. Burrows
Robert L. Bender
J. Christopher Naftel
Unknown Author
Giuseppe De Chiara
Alexander Bolonkin
European Forum on Space Transportation Systems (2nd 1993 Nancy, France)
S. P. Umanskiĭ
American Institute of Aeronautics and Astronautics
Lei Shi
Roger Chevalier