Butterfield, D., Draper, D., Ricard, M., Myrer, J., Durrant, E., & Schulthies, S. (1997). The effects of high-volt pulsed current electrical stimulation on delayed-onset muscle soreness. Journal of athletic training, 32(1), S. 15-20. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1319229/pdf/jathtrain00013-0017.pdf

Butterfield, D.L., D.O Draper, M.D Ricard, J.W Myrer, E. Durrant, and S.S Schulthies. "The Effects of High-volt Pulsed Current Electrical Stimulation On Delayed-onset Muscle Soreness." Journal of Athletic Training 32, no. 1 (1997): S. 15-20.

Butterfield, D.L., et al. "The Effects of High-volt Pulsed Current Electrical Stimulation On Delayed-onset Muscle Soreness." Journal of Athletic Training 32.1 (1997): S. 15-20.