- American Philosophical Society: Alfred Russel Wallace Collection MSS.B.W15a
- Maidstone Museum and Bentlif Art Gallery: Benjamin Harrison Archive, Volume 15, p.33
- Harrison, E. R. (1928). In: Harrison of Ightham: a Book about Benjamin Harrison, of Ightham, Kent, Made up Principally of Extracts from His Notebooks and Correspondence. Oxford: Oxford University Press. [p. 171]
No summary available.