1. Behavior of humans in variable-interval schedules of reinforcement;Bradshaw;Journal of the Experimental Analysis of Behavior,1976
2. Effect of punishment on human variable-interval performance;Bradshaw;Journal of the Experimental Analysis of Behavior,1977
3. A quantitative analysis of the responding maintained by interval schedules of reinforcement;Catania;Journal of the Experimental Analysis of Behavior,1968
4. Depression: Loss of reinforcers or loss of reinforcer effectiveness;Costello;Behavior Therapy,1972
5. Choice in concurrent schedules and a quantitative formulation of the law of effect;de Villiers,1977