List of sources:
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Agricultural Journal of the Cape of Good Hope, 1907, Vol. 31; 1910, Vol. 36.
Cape Chemical Society. Proceedings, 1906-1912.
Cape of Good Hope. Civil service list, 1910.
Cape of Good Hope. Report of the Director of Agriculture, 1909.
Cape of Good Hope. Report of the Senior Analyst, 1899, 1901, 1902, 1906.
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Dictionary of South African biography, Vol. 3, 1977 (Ethelreda Lewis).
FamilySearch: Joseph Lewis. https://www.familysearch.org/ark:/61903/1:1:6ZH5-4D5J?lang=en
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Ritchie, W. The history of the South African College, 1829-1918. Cape Town: T. Maskew Miller, 1918.
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