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"Genus: Coreopsis L."Germplasm Resources Information Network. United States Department of Agriculture. January 6, 2011. Archived from the original on June 29, 2011. Retrieved February 9, 2011.
"Species Records of Coreopsis". Germplasm Resources Information Network. United States Department of Agriculture. Archived from the original on January 20, 2009. Retrieved February 9, 2011.