1. 1) O'Neil: Physics Today, 32-40, Sept. 1974.
2. 2) Johnson & Holbrow: NASA SP-413, 1977.
3. 3) O'Leary: Project Space Station, Stackpole Books, 1983.
4. 4) Glaser: Science, 162, p. 857, 1968.
5. 5) Alexander: The Space Station, M. Friedman Publishing Group, Inc., 1988.