1. The economic impact of the horse industry on the United States;American Horse Council (AHC),2005
2. Manure production and characteristics;American Society of Agricultural Engineers (ASAE),2005
3. Summary and implications;Ashmead,1985
4. Official publication;Association of American Feed Control Officials (AAFCO),2012
5. The effect of supplemental inorganic and organic sources of copper and zinc onbone metabolism in exercised yearling geldings;Baker,2003