1. Martin, W. R. Pharmac. Rev. 19, 463–521 (1967).
2. Jacobson, A. E. & May, E. L. in Narcotic Antagonists, 187–189 (Raven, New York, 1973).
3. Oh-ishi, T. & May, E. L. J. med. Chem. 16, 1376–1378 (1973).
4. Harris, L. S. in Narcotic Antagonists, 13–20 (Raven, New York, 1973).
5. Langbein, A., Merz, H., Stockhaus, K. & Wick, H. in Narcotic Antagonists, 157–165 (Raven, New York, 1973).