1. A. F. Casy and R. T. Parfitt, Opioid Analgesics, Chemistry and Receptors (Plenum Press, New York, 1986).
2. pp. 473–496.
3. A. F. Casy, Adv. Drug Res., 18, 177–289 (1989).
4. G. R. Lenz, S. M. Evans, D. E. Walters, and A. J. Hopfinger, Opiates (Academic Press, Orlando, Florida, 1986).
5. pp. 166–187, 377–399, 448–458, and 513–541.