Regier DA, Watson V, Burnett H, Ungar WJ. Task complexity and response certainty in discrete choice experiments: an application to drug treatments for juvenile idiopathic arthritis. J Behav Exp Econ. 2014 Jun;50:40-9. doi: 10.1016/j.socec.2014.02.009
Walker EA, Picker MJ, Granger AL, Dykstra LA. Effects of opioids in morphine-treated pigeons trained to discriminate among morphine, the low-efficacy agonist nalbuphine, and saline. J Pharmacol Exp Ther. 2004 Jul;310(1):150-8.
Allen RM, Granger AL, Dykstra LA. The competitive N-methyl-D-aspartate receptor antagonist (-)-6-phosphonomethyl-deca-hydroisoquinoline-3-carboxylic acid (LY235959) potentiates the antinociceptive effects of opioids that vary in efficacy at the mu-opioid receptor. J Pharmacol Exp Ther. 2003 Nov 1;307(2):785-92.
Allen RM, Granger AL, Dykstra LA. Dextromethorphan potentiates the antinociceptive effects of morphine and the delta-opioid agonist SNC80 in squirrel monkeys. J Pharmacol Exp Ther. 2002 Feb 1;300(2):435-41.