^Darwin, Charles (1866). «Historical Sketch». On the Origin of Species by means of natural selection (4th & subsequent utg.). London: Murray. «[Wells] distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated.»
^Julia Blackburn (1989). Charles Waterton, 1782-1865: traveller and conservationist. London: The Bodley Head. s. 52–9. ISBN0-370-31248-1.
^Bertomeu-Sánchez, José Ramón; Nieto-Galan, Agustí, red. (2006). Chemistry, Medicine and Crime: Mateu J. B. Orfila (1787–1853) and his times. Sagamore Beach, MA: Science History Publications. ISBN0-88135-275-6.CS1-vedlikehold: Flere navn: redaktørliste (link)