1. Ahearn, D. G., Hall, E. T., Jr., and Reinhardt, D. J.: 1971, Bioscience 21, 115.
2. American Public Health Association: 1965, Standard Methods for the Examination of Water and Waste Water, 12th ed., American Public Health Association, Inc., New York, 769 pp.
3. Bovee, E. C.: 1970, Arch. Protistenk. 112, 178.
4. Cook, W. L., Ahearn, D. G., and Reinhardt, D. J.: 1972, Abstracts Annual Meeting, American Society for Microbiology, E-143, 24.
5. Jeon, K. W.: 1973, The Biology of the Amoeba, Academic Press, New York, 628 pp.