Botanical Exploration of Southern Africa : :An illustrated history of early botanical literature on the Cape Flora, Biographical accounts of the leading plant collectors and their activities in southern Africa form the days of the East India Company until the modern times - Glen, H.F. (SANBI, 2010)

Carnegie Institution of Washington publication - Carnegie Institution of Washington (Carnegie Institution of Washington, 1924)

Carnegie Institution of Washington publication - Carnegie Institution of Washington (Carnegie Institution of Washington, 1924)

Checklist of CITES Species (1998)

Checklist of CITES Species and Annotated CITES Appendices and Reservations - Inskipp, Tim (CITES Secretariat, UNEP-WCMC, 2005)

Checklist of CITES Species: a reference to the appendices to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (2001)

Checklist of CITES Species: a reference to the appendices to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (1996)

Checklist of CITES Species: a reference to the appendices to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (2003)

The Gardeners' chronicle :a weekly illustrated journal of horticulture and allied subjects ([Gardeners Chronicle], 1913)