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Cape of Good Hope. Civil service list, 1896, 1899.
Cape of Good Hope. Report of the Trustees of the South African Museum, 1906, 1907, 1909.
FamilySearch: Henry Miller Oakley. https://ancestors.familysearch.org/en/L2HN-1WN/henry-miller-oakley-1862-1920 AND https://www.familysearch.org/ark:/61903/3:1:33S7-95FZ-9CL9?view=index&personArk=/ark:/61903/1:1:WD65-CKW2&action=view&cc=1779109&lang=en&groupId=M96D-MLC
Hall, A.L. A bibliography of South African geology to the end of 1920. Pretoria: Geological Survey, Memoir No. 18, 1922.
Henry Miller Oakley. Geni. Retrieved from https://www.geni.com/people/Henry-Miller-Oakley/6000000020323075199
on 2019-1-11.
Malherbe, D.F. du T. Family register of the South African nation (3rd ed.) Stellenbosch: Tegniek, 1966.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Oakley, Henry Miller / Oakley, H.M.
South African Association for the Advancement of Science. Report, 1903, 1905/6, lists of members.
South African bibliography to the year 1925. London: Mansell, 1979.