Powers, M. E.. (2002). The safety and efficacy of anabolic steroid precursors: What is the scientific evidence? Journal of athletic training, 37(3), S. 300-305. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC164360/pdf/attr_37_03_0300.pdf

Powers, Michael E. "The Safety and Efficacy of Anabolic Steroid Precursors: What Is the Scientific Evidence?" Journal of Athletic Training 37, no. 3 (2002): S. 300-305.

Powers, Michael E. "The Safety and Efficacy of Anabolic Steroid Precursors: What Is the Scientific Evidence?" Journal of Athletic Training 37.3 (2002): S. 300-305.