Van der Walt, Pieter and le Riche, Elias. 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} }