BRUNER, C. A., L. M. GALLARDO, and R. AVILA. “Varying the Temporal Placement of a Signal Within a Constant Response-Independent Food Cycle on the Activity of Rats”. Mexican Journal of Behavior Analysis, vol. 28, no. 1, Jan. 2011, pp. 3-18, doi:10.5514/rmac.v28.i1.23558.