List of sources:
Bayer, A.W. Aspects of Natal's botanical history. South African Journal of Science, 1971, Vol. 67, pp. 401-411.
Botanical News. Journal of Botany, British and Foreign,
1866, Vol. 4, p. 367. Retrieved from http://biodiversitylibrary.org/page/16233429 on 2017-1-12.
Dictionary of South African biography, Vol. 3, 1977.
Gunn, M. & Codd, L.E. Botanical exploration of southern Africa. Cape Town: Balkema, 1981.
Harvey, W.H. & Sonder, O.W. Flora Capensis, being a systematic description of the plants of the Cape Colony, Caffraria, and Port Natal (Vol. 2 and 3). Ashford, Kent: Lovell Reeve, 1894 (originally published 1862, 1865).
McCracken, D.P. A new history of the Durban Botanic Gardens. Durban: Parks Department, 1996.
McCracken, D.P. & McCracken, P.A. Natal, the garden colony. Sandton: Frandsen, 1990.
McKen, M.J. The ferns of Natal. Natal almanac and yearly register, 1870, pp. 33-60.
Natal Mercury, 21 August 1869, p. 3, "The late William Tyrer Gerrard".
Schrire, B.D. Centenary of the Natal Herbarium. Bothalia, 1983, Vol. 14, pp. 223-236.