Perkins, C. C., Beavers, W. O., Hancock, R. A., Hemmendinger, P. C., Hemmendinger, D., & Ricci, J. A. (1975). Some variables affecting rate of key pecking during response-independent procedures (autoshaping).

Perkins, Charles C., William O. Beavers, Robert A. Hancock, Patricia C. Hemmendinger, Dennis Hemmendinger, ja John A. Ricci. Some Variables Affecting Rate of Key Pecking During Response-independent Procedures (autoshaping). 1975.

Perkins, Charles C., et al. Some Variables Affecting Rate of Key Pecking During Response-independent Procedures (autoshaping). 1975.