List of sources:
Agricultural Journal (Union of South Africa), 1911-1913, Vol. 2 and 6.
Agricultural Journal of the Cape of Good Hope, 1898-1899, Vol. 12-15; 1907-1910, Vol. 31-36.
Brown, J.M.M. The history of "Geeldikkop" research. Journal of the South African Veterinary Medical Association, 1959, Vol. 30, pp. 97-111.
Cape of Good Hope. Civil service list, 1896.
Cape of Good Hope. Report of the Colonial Veterinary Surgeon, 1897-1899.
Curson, H.H. The veterinary profession in South Africa... Cape of Good Hope Veterinary Medical Society. Journal of the South African Veterinary Medical Association, 1931, Vol. 2, pp. 95-101.
FamilySearch: Roland William Dixon. https://www.familysearch.org/search/record/results?q.anyPlace=South Africa&q.givenName=Roland William&q.surname=Dixon
Henning, M.W. Animal diseases in South Africa (2 vols). Central News Agency, 1932.
Journal of the South African Veterinary Medical Association, 1927, Vol. 1(1), p. 84-85, List of members; 1929, Vol. 1(3), pp. 77-83, Register of veterinarians of the Uion of South Africa.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Dixon, Roland William/Dixon, R.W.
Posthumus, P.J. Past Veterinarians in South Africa (10th edition), Vol. 2, [1992].
Union of South Africa. Public service list, 1914.
University of the Cape of Good Hope. Calendar, 1917/8.