List of sources:
Cape of Good Hope. Report of the Surveyor-General, 1885.
FamilySearch: Philip Bourchier Sherard Wrey. https://www.familysearch.org/en/tree/person/details/KH5R-NV8
General directory and guide book to the Cape of Good Hope and its dependencies, 1886, pp. 111-112, list of sworn land surveyors.
Mendelssohn, S. South African bibliography. London, 1910.
National Automated Archival Information Retrieval System (NAAIRS). http://national.archives.gov.za/naairs.htm Documents relating to Wrey, Philip B.S. / Wrey, P.B.S.
Rhodesial Scientific Association. Proceedings, 1906-7, Vol. 6 (list of members), Vol. 7 (paper by Wrey); 1918, Vol. 16 and 1931, Vol. 30 (lists of members).
Sir Philip Bourchier Sherard Wrey, 12th Bt. The Peerage. Retrieved on 23 June 2021 from http://www.thepeerage.com/p61451.htm
University of the Cape of Good Hope. Calendar, 1884/5.
Who was who, Vol. 3, 2nd ed. London: Adam & Black, 1967.
Wills, W.H. The Anglo-African who's who and biographical sketch book. London: Upcott, 1910.