Freegard, G., Bradshaw, C. A., & Reed, P. (2015). Human performance on random ratio and random interval schedules, performance awareness and verbal instructions. Learning & Behavior, 43(3), pp. 272-288. doi:10.3758/s13420-015-0178-x

Freegard, Gary, Ceri A. Bradshaw, and Phil Reed. "Human Performance On Random Ratio and Random Interval Schedules, Performance Awareness and Verbal Instructions." Learning & Behavior 43, no. 3 (2015): 272-288.

Freegard, Gary, Ceri A. Bradshaw, and Phil Reed. "Human Performance On Random Ratio and Random Interval Schedules, Performance Awareness and Verbal Instructions." Learning & Behavior 43.3 (2015): 272-288.