APA (7th ed.) Citation

Walt, J. J. A. v. d., Vorster, P., & Ward-Hilhorst, E. Pelargoniums of Southern Africa. Juta.

Chicago Style (17th ed.) Citation

Walt, J. J. A. van der, Pieter Vorster, and Ellaphie Ward-Hilhorst. Pelargoniums of Southern Africa. Cape Town u.a: Juta.

MLA (9th ed.) Citation

Walt, J. J. A. van der, et al. Pelargoniums of Southern Africa. Juta.