Rocketry Through the Ages - a pictorial presentation from the NASA Marshall Space Flight Center History Office
The New York Times on AOL: Sputnik - newspaper articles from the early days of space exploration
Army in Space - early space exploration by the U.S. Army and NASA
Sputnik 40th Anniversary
NASA Image eXchange - searchable archive of NASA images
Soviet Dogs in Space: Their Stories on Stamps
Bergwin, Clyde R., and William T. Coleman, Animal astronauts; they opened the way to the stars, 207 p. illus., Prentice-Hall, Englewood Cliffs, N.J., 1963.
Diamond, Edward, and Stephen Bates, Sputnik, American Heritage, vol. 48, no. 6, pp. 84-93, October 1997.
Rey, H. A., Curious George Gets a Medal, Houghton Mifflin Company, New York, 1993.
If you have trouble finding some of these books at your local public library, try a university medical school library or school of veterinary medicine library. You can also try searching library catalogs for Library of Congress subjects "Space medicine--Research" or "Aviation medicine" for further information.
The University of Minnesota Space Physics Home Page