Bruner, Carlos A., and Raúl Ávila. “Acquisition and Maintenance of Lever Pressing by Rats Without Explicit Reinforcer Deprivation”. Mexican Journal of Behavior Analysis 28, no. 2 (July 31, 2011): 107–103. Accessed May 12, 2024. https://revistas.unam.mx/index.php/rmac/article/view/26324.