1. Endogenous opioid peptides: Multiple agonists and receptors;Lord;Nature,1977
2. History and development of mixed opioid agonists, partial agonists and antagonists;Martin;Br. J. Clin. Pharmacol.,1978
3. Opiate receptors and opioid peptides;Snyder;Neuroscience,1979
4. Comparative effects of analgesics on pain threshold, respiratory frequency and gastrointestinal propulsion;Green;Br. J. Pharmacol.,1959
5. A neurohumoral substance discharged into blood perfusate from isolated rabbit heads by intracerebral morphine;Margolin;Med. Pharmacol. Exptl.,1965