Walt, Pieter Van der & Elias le Riche. 1999. The Kalahari and its plants. Pretoria: s.n.
@book{vanderwalt1999,
address = {Pretoria},
author = {Van der Walt, Pieter and le Riche, Elias},
publisher = {s.n.},
title = {The Kalahari and its plants},
year = {1999}
}