- Cambridge University Library: DAR 106: B86-87
- British Library, The: BL Add. 46434 f. 188
- Wallace Family Collection (private collection)
- Marchant, J. (Ed.). (1916). In: Alfred Russel Wallace; Letters and Reminiscences. Vol. 1. London & New York: Cassell & Co. [pp. 246-247]
No summary available.