by M. R. Johnson and F. G. Le RouxRepublic of South Africa, Dept. of Mineral and Energy Affairs, Geological Survey : Obtainable from the Govt. Printerc1994
by N. Keyser and C.P. Du PlessisRepublic of South Africa, Dept. of Mineral and Energy Affairs, Geological Survey : Obtainable from the Govt. Printerc1993
compiled by D.J.L.Visser from reports by D.J.L. Visser ... [et al.]Republic of South Africa, Department of Mineral and Energy Affairs, Geological Surveyc1989