De Witte, P., & Gewiss, M. (1986). Effects of Variations of Reinforcement Magnitude On Alcohol Discrimination Using Intracranial Stimulation As the Reinforcer. Physiology & Behavior, 36(6), 1005-1008. https://doi.org/10.1016/0031-9384(86)90471-3 (Original work published 1986)