List of sources:
Agricultural Journal of the Cape of Good Hope, July 1903, Vol. 23(1), pp. 18-19: Farewell to Mr W.G. Mason.
Cape of Good Hope. Report of Mr W. Mason, ex-principal, Elsenburg, on the working of the Agricultural College at Elsenburg during his tenure of office as principal of the institution. (Parliamentary Report G3-1904).
Cape of Good Hope. Report of the Principle of the Agricultural School at Elsenburg, 1898-1903.
Department of Agricultural Technical Services, Winter Rainfall Region. Elsenburg: Yesterday, today and tomorrow. Commemorative edition, 1898-1978.
FamilySearch: William Grice Mason. https://www.familysearch.org/en/tree/person/details/GZHR-FLP
National Union Catalogue, pre-1956 imprints. London: Mansell, 1968-1980.
South African Association for the Advancement of Science. Report, 1903, lists of members and office bearers.
South African Philosophical Society. Transactions, 1900, Vol. 11, list of members.
Standard Encyclopaedia of Southern Africa (SESA). Cape Town: NASOU, 1970-1976.
Wood, Richard (great-great-grandson of W.G. Mason). Personal communications, 5-6 April 2020.