Wilkins, John S. (2006). "Species, kinds, and evolution". Reports of the National Center for Science Education. Archived from the original on 2012-01-22. Retrieved 2009-09-24.
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Wilkins, John S. (2006). "Species, kinds, and evolution". Reports of the National Center for Science Education. Archived from the original on 2012-01-22. Retrieved 2009-09-24.