Madness", PETA Comis, Don, USDA AgriculturalResearchService. "Settling Doubts about Livestock Stress." i AgriculturalResearch. Marts 2005. s. 4-7. Smith
af botanikere hos United States Department of Agriculture: AgriculturalResearchService (ARS) Ligustergedeblad (Lonicera pileata) Myrtegedeblad (Lonicera