C. W. Spurr

A classically conditionable skeletal response can be acquired with a discriminated punishment contingency

W. F. Prokasy, W. C. Williams, C. G. Clark, 1974 .

Conditioned response-contingent delays of the unconditioned stimulus in human aversive conditioning.

W. F. Prokasy, W. C. Williams, C. G. Clark, 1975, Journal of experimental psychology. Human learning and memory.

Preexposure to explicitly unpaired conditioned and unconditioned stimuli retards conditioned response emergence

W. F. Prokasy, C. W. Spurr, N. Goodell, 1978 .