1. Bergel, F.,et al., in: Chemistry and Biology of Purines. (Ciba Foundation Symposion, p. 256) London: Churchill 1957
2. DeLamirande, G., Allard, C., Cantaro, A.: Cancer Res.18, 952 (1958).
3. Feigelson, Ph.,et al.: ibid.19, 1230 (1959)
4. Watts, R. W. E.,et al.: Nature201, 395 (1964).
5. Watts, R. W. E., Watts, J. E. M., Seegmiller, J. E.: J. Lab. Clin. Med.66, 688 (1965)