1. Atkinson, M. R., Jackson, J. F., and Morton, R. K., Nature, 192, 946 (1961).
2. Hughes, N. A., Kenner, G. W., and Todd, A., J. Chem. Soc., 3733 (1957).
3. Ultraviolet Absorption Spectra of 5′-Ribonucleotides: Circ. OR-10, 18 (Pabst Laboratories, 1956); Pabst Research Biochemicals, Circ. OR-17, 33 (Pabst Laboratories, 1961).
4. Buchanan, J. M., and Hartman, S. C., Adv. in Enzymol., 21, 199 (1959).
5. See Brockman, R. W., Cancer Res., 20, 643 (1960). Paterson, A. R. P., Canad. J. Biochem. Physiol., 40, 195 (1962).