http://well.blogs.nytimes.com/2012/05/10/concussions-may-be-more-severe-in-girls-and-young-athletes/
http://well.blogs.nytimes.com/2010/09/22/can-concussions-in-kids-cause-problems-later-in-life/
http://blogs.smithsonianmag.com/smartnews/2012/10/five-kid-concussions-in-one-game-has-parents-questioning-pop-warner-football/
http://profootballtalk.nbcsports.com/2012/05/03/kurt-warner-would-prefer-his-sons-not-play-football/