1. Beckett, A. H.: Stereochemical factors in biological activity. Fortschr. Arzneimittelforsch. 1, 455?530 (1959)
2. Beckett, A. H., Greenhill, J. V.: Weakly basic analoguous of potent analgesics. J. med. pharm. Chem. 4, 423?436 (1961)
3. Bentley, K. W., Lewis, J. W.: The relationship between structure and activity in the 6,14-endoethenotetrahydrothebaine series of analgesics. In: Agonist and antagonist action of narcotic analgesic drugs, pp. 7?16. London: The Macmillan Press Ltd. 1972
4. Biers, H., Stevenson, G. W.: The active form of the narcotic analgesic molecule. Fed. Proc. 19, 272 (1960)
5. Bird, A. E., Marshall, A. C.: Correlation of serum binding of penicillins with partition coefficients. Biochem. Pharmacol. 16, 2275?2290 (1967)