1. Improving health through youth sports: is participation enough?;Bergeron;New Dir Youth Dev,2007
2. National Sporting Goods Association. 2008 Participation–ranked alphabetically. Available at: www.nsga.org/files/public/2008ParticipationRankedbyAlpha_4Web_080415.pdf. Accessed November 20, 2009
3. American Youth Soccer Organization. About AYSO. Available at: www.ayso.org/AboutAYSO.org. Accessed June 19, 2009
4. US Youth Soccer Association. History: US soccer. Available at: www.usyouthsoccer.org/aboutus/WhatIsYouthSoccer.asp. Accessed June 19, 2009
5. National Federation of High Schools. 2008–09 High School Athletics Participation Study. Available at: www.nfhs.org/content.aspx?id=3282&linkidentifier=id&itemid=3282. Accessed November 20, 2009