1. Beach, H. D.: Morphine addiction in rats. Canad. J. Psychol. 11, 104?112 (1957).
2. CIBA Pharmaceutical Co., Ltd.: An introductory report on Ciba 20?684-Ba. A new benzimidazole derivative with a highly potent analgesic action. Basle 1958.
3. Deneau, G. A., D. A. McCarthy and M. H. Seevers: Physical dependence liability studies in the monkey. Add. 1, Min. 20th Meet., Comm. Drug Addiction and Narcotics, Natl. Res. Council, Natl. Acad. Sci., Washington, D.C., 10?11 January 1959.
4. Finney, D. J.: Statistical method in biological assay. New York: Hafner Publishing Co. 1952.
5. Fraser, H. F., H. Isbell and A. B. Wolbach, Jr.: Addictiveness of new synthetic analgesics. Add. 2, Min. 21st Meet., Comm. Drug Addiction and Narcotics, Natl. Res. Council, Natl. Acad. Sci., Washington, D.C., 11?12 January 1960.