- Hope Entomological Library, Oxford University Museum of Natural History: ARW 52
- Hope Entomological Library, Oxford University Museum of Natural History: ARW 52
- Marchant, J. (Ed.). (1916). In: Alfred Russel Wallace; Letters and Reminiscences. Vol. 2. London & New York: Cassell & Co. [pp. 61-62]
About having met Darwin once briefly at British Museum before going East. Comments on Poulton's "Theories of Evolution".