Reed, P., Schachtman, T. R., & Hall, G. (1988). Potentiation of responding on a VR schedule by a stimulus correlated with reinforcement: Effects of diffuse and localized signals. Animal Learning & Behavior, 16(1), pp. 75-82. doi:10.3758/BF03209046

Reed, Phil, Todd R. Schachtman, and Geoffrey Hall. "Potentiation of Responding On a VR Schedule By a Stimulus Correlated With Reinforcement: Effects of Diffuse and Localized Signals." Animal Learning & Behavior 16, no. 1 (1988): 75-82.

Reed, Phil, Todd R. Schachtman, and Geoffrey Hall. "Potentiation of Responding On a VR Schedule By a Stimulus Correlated With Reinforcement: Effects of Diffuse and Localized Signals." Animal Learning & Behavior 16.1 (1988): 75-82.