1. Hartwick, R.A. and Brown, P.R:J. Chromatogr.,126, 679 (1976).
2. Salvator, F., Colonna, A., Costanzo, F., Russo.T., Esposito, F., and Cimino, F.: “Modified Nucleo-sides and Cancer”, Springer-Verlag, Berlin (1983).
3. Gehrke, C.W., Kuo, K.C., and Zumwalt, R.W.:J. Chromatogr,188, 129(1980).
4. Gehrke, C.W., McCune, R.A., Gama-Sosa, M.A., Ehrlich, M., and Kuo, K.C.:J. Chromatogr,301, 199(1984).
5. Michelson, A.M.: “The Chemistry of Nucleosides and Nucleotides”, Academic, London (1963).