1. Barrett JE (1976) Effects of alcohol, chlordiazepoxide, cocaine and pentobarbital on responding maintained under fixed-interval schedules of food or shock presentation. J Pharmacol Exp Ther 196:605?615
2. Davis WM, Holbrook JM, Babbini M (1973) Differential effects of morphine on active avoidance as a function of pre-drug performance. Pharmac Res Commun 5:47?53
3. Downs DA, Woods JH (1976) Morphine, pentazocine and naloxone effects on responding under a multiple schedule of reinforcement in rhesus monkey and pigeons. J Pharmacol Exp Ther 196:298?306
4. Advances in biochemical psychopharmacology;SG Holtzman,1973
5. Holtzman SG (1976) Effects of morphine and narcotic antagonists on avoidance behavior of the squirrel monkey. J Pharmacol Exp Ther 196:145?155