van Wyhe, John (27 March 2007). "Mind the gap: Did Darwin avoid publishing his theory for many years?" (PDF). Notes and Records of the Royal Society 61 (2): 177–205. doi:10.1098/rsnr.2006.0171. Abgerufen am 7. Februar 2008, pp=181–182.
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There are three examples of the word 'evolution' in Social Statics, but none in the sense that is used today in biology. See Herbert Spencer: Social Statics
