Broglio, S. P., Ju, Y., Broglio, M. D., & Sell, T. C. (2003). The efficacy of soccer headgear. Journal of athletic training, 38(3), S. 220-224. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC233175/pdf/attr_38_03_0220.pdf

Broglio, Steven P., Yan-Ying Ju, Michael D. Broglio, and Timothy C. Sell. "The Efficacy of Soccer Headgear." Journal of Athletic Training 38, no. 3 (2003): S. 220-224.

Broglio, Steven P., Yan-Ying Ju, Michael D. Broglio, and Timothy C. Sell. "The Efficacy of Soccer Headgear." Journal of Athletic Training 38.3 (2003): S. 220-224.