http://en.wikipedia.org/wiki/American_football_strategy

http://football.about.com/cs/a/52defense.htm

http://www.ehow.com/how_4538_run-football-defense.html

http://www.fbforyouth.com/5-2monster.html

http://www.ehow.com/video_2287707_containment-52-football-defense.html

http://www.championshipproductions.com/cgi-bin/champ/c/Football/5-2-Defense-427.html

http://www.jerrycampbellfootball.com/index.php?main_page=product_info&products_id=8

http://www.thefreelibrary.com/Counter+blast+the+5-2+defense!+(football)-a020584234

http://www.ehow.co.uk/video_2287715_versatility-52-football-defense.html

http://www.highbeam.com/doc/1G1-20584234.html

http://wearesc.com/forums/archive/index.php/t-100013.html

http://www.cdi.org/weekly/1998/Issue05/

http://www.nextag.com/5-2-defense-football/shop-html

http://findarticles.com/p/articles/mi_m0FIH/is_n9_v67/ai_n18607794/

http://www.rpbridge.net/6h05.htm

http://www.nextag.com/4-2-5-football-defense/search-html

http://www.coachpeelfootball.com/53defense.htm

http://www.youtube.com/watch?v=SlhQFsCA2ZY

http://ballstatesports.com/ViewArticle.dbml?SPSID=62140&SPID=6783&DB_OEM_ID=14200&ATCLID=1441821

http://www.championshipproductions.com/cgi-bin/champ/p/Football/The-50-Defense_FD-02660.html?id=ruDXcWgs