1. L. E. Kaechele and A. E. Olshaker, “Meteoroids—implications for the design of space structures” (Institute of Aeronautical Sciences Manned Space Stations Symposium, Los Angeles, California, April, 1960).
2. F. L. Whipple, “Possible hazards to a satellite vehicle” [Project RAND, Douglas Aircraft Corporation, Santa Monica, California, 1946 (Secret)].
3. F. J. Willig and H. W. Semon, “A multistage H. E. actuated hypervelocity gun” (Proceedings of Third Symposium on Hypervelocity Impact, Armour Research Foundation February, 1959), pp. 507–509.
4. R. L. Bjork, “Effects of a meteoroid impact on steel and alumiunm in space” (RAND Corporation, Santa Monica, California, paper P-1662, December, 1958); included inProceedings of the Tenth International Astronautical Congress, London, 1959(Springer-Verlag, Vienna, 1960).
5. J. H. Kinecke, Jr., “An experimental study of crater formation in lead” (Proceedings of Third Symposium on Hypervelocity Impact, Armour Research Foundation, February, 1959). pp. 157–182.