List of sources:
Cullingworth's Natal almanac, 1890.
Durban Botanic Society. Report, Natal Botanic Gardens, 1884, 1891, 1897. (Don Africana Library, Durban; classification no. 590.744).
General directory and guide book to the Cape of Good Hope and its dependencies..., 1871-1874, 1881, 1891, 1892.
Henderson, W.P.M. Durban: Fifty years' municipal history. Durban: Robinson & Co., 1904.
Natal almanac, directory, and yearly register, 1867-1869, 1872-1874, 1879, 1881, 1885, 1898, 1899.
Natal Colonist, 8 May 1879, p. 2, Natal Microscopical Society.
Natal Government Gazette, 7 September 1880, pp. 644-661: List of voters for members of the Legislative Council for the township or borough of Durban...
National Automated Archival Information Retrieval System (NAAIRS). http://national.archives.gov.za/naairs.htm Documents relating to Steel, John Stollery / Steel, J.S.
Plug, C. The Natal Microscopical Society (1878-1885?). Natalia, 1992, No. 22, pp. 49-54.
Quickelberge, C. Collections and recollections: The Durban Natural History Museum, 1887-1987. Durban Natural History Museum, 1987.