List of sources:
Burrows, E.H. A history of medicine in South Africa. Cape Town: Balkema, 1958.
Cape of Good Hope Meteorological Commission. Report, 1893, 1896, 1897, 1899.
Death notice: John Nunn Eagle. eGGSA Documents,
at http://www.eggsa.org/documents/main.php?g2_itemId=587297
Dictionary of South African biography, Vol. 5, 1987.
FamilySearch: John Nunn Eagle. https://www.familysearch.org/ark:/61903/1:1:6ZL2-6NVB and https://www.familysearch.org/ark:/61903/3:1:939J-679J-M?view=index&personArk=/ark:/61903/1:1:7J5F-33PZ&action=view
Laidler, P.W. & Gelfand, M. South Africa - its medical history, 1652-1898. Cape Town: Struik, 1971.
Lyle, J. Meteorology: Past, present and future work in the Orange River Colony. Transactions of the Philosophical Society of the Orange River Colony, 1903-1907, Vol. 1, pp. 20-23.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to John Nunn Eagle / J.N. Eagle.
South African bibliography to the year 1925. London: Mansell, 1979.
South African medical directory for 1897. Cape Town: Cape Times, 1897.
South African Medical Journal, 2nd series, 1898, Vol. 5, pp. 240-242: list of members [of the SA Medical Association].