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4. Anonymous, 2011b. Annual North American Registered Foal Crop. The Jockey Club 2011 Online Fact Book. http://www.jockeyclub.com/factbook.asp?section=2 (accessed 03.03.11).
5. Factors associated with time until first race and career duration for Thoroughbred racehorses;Bailey;Am. J. Vet. Res.,1999