Carpio, C., V. Pacheco, G. Ambriz, and E. Ribes. “Effects of Probability and Magnitude of Reinforcement in a Temporal Schedule With Different Response Requirements”. Mexican Journal of Behavior Analysis, vol. 15, no. 1y2, Jan. 2011, pp. 55-67, doi:10.5514/rmac.v15.i1y2.23467.