http://www.marathonguide.com/races/races.cfm
http://www.coolrunning.com/index.shtml
http://www.active.com/
http://www.runningtimes.com/rt/articles/?id=6765
http://runningtimes.com/rt/articles/?id=6763
http://www.rnraz.com/home.html
http://bostonmarathon.com/
http://www.usatf.org/assoc/az/