1. Gitlin, D., and Boesman, M., J. Clin. Invest., 46, 1010 (1967).
2. Gitlin, D., and Kitzes, J., Biochim. Biophys. Acta, 147, 334 (1967).
3. Arey, L. E., Developmental Anatomy, seventh ed. (Saunders, Philadelphia, 1965).
4. Gitlin, D., and Biasucci, A., J. Clin. Invest., 48, 1433 (1969).
5. Jacobsen, C. S., Leonis, J., Linderstrøm-Lang, K., and Ottesen, M., Methods Biochem. Anal., 4, 171 (1957).