1. Meisenheimer, M., Z. Wiss. Zool., 148, 261 (1936).
2. Hickman, C. P., Nature, 189, 1012 (1961).
3. Lushbaugh, C. C., presented at the Hearings on Applications of Radio-isotopes and Radiation in the Life Sciences, Congressional Sub-committee on Research, Development, and Radiation of the Joint Committee on Atomic Energy, Congress of the United States, Eighty-seventh Congress, March 27–30, 1961, 27 (U.S. Govt. Printing Office, Washington, D.C., 1961).
4. Lushbaugh, C. C., Hale, D. B., and Richmond, C. R., Los. Alamos Sci. Lab. Rep. LAMS-2526, 364 (1961).
5. Woodward, K. T., Richmond, C. R., Langham, W., Proc. Health Phys. Soc. Meeting, 79 (June, 1956).