Stan Jensen's Run 100s site: http://www.run100s.com/

New York Ultra Running: http://www.newyorkultrarunning.org/

Finger Lakes Fifties: http://www.fingerlakesrunners.org/races/forms/Fifties.html

UltraRunning Online: http://www.ultrarunning.com/

Trail Runner Trophy Series Races: http://www.trailrunnermag.com/racecalendar.php?ts=yes

Kevin Sayers Ultra Running Resource Page: http://www.ultrunr.com/

American Ultra Running Association: http://www.americanultra.org/