Emotions. Notes References Adrian Desmond and James Moore, Darwin (London: Michael Joseph, the Penguin Group, 1991). The Correspondence of Charles Darwin On the various contrivances by which British and foreign orchids are fertilised by insects The variation of animals and plants under domestication Further reading The Complete Works of Charles Darwin Online – Darwin Online; Darwin's publications, private papers and bibliography, supplementary works including biographies, obituaries and reviews. Free to use, includes items not in public domain. ; public domain Darwin Correspondence Project Text and notes for most of his letters Charles Darwin