1. Anhaeusser, C.R. (2012). The history of mining in the Barberton greenstone belt, South Africa, with an emphasis on gold (1868–2012). Economic Geology Research Institute, School of Geosciences, University of the Witwatersrand, Johannesburg Google Scholar. https://dewilde.co.za/Barberton/GoldenQuarry/THE%2520HISTORY%2520OF%2520MINING%2520%2520BARBERTON%2520-%2520Carl%2520Anhaesseur.pdf. Accessed on 23 Nov 2018
2. Armstrong, R. A., Compston, W., Retief, E. A., Williams, I. T., & Welke, H. J. (1991). Zircon ion microprobe studies bearing on the age and evolution of the Witwatersrand triad. Precambrian Research, 53(3–4), 243–266.
3. Banerjee, B., & Gupta, S. K. (1975). Hidden layer problem in seismic refraction work. Geophysical Prospecting, 23(4), 642–652.
4. Breytenbach, I. J., & Bosch, P. J. A. (2011). Application, advantages and limitations of high-density gravimetric surveys compared with three-dimensional geological modelling in dolomite stability investigations. Journal of the South African Institution of Civil Engineering, 53(2), 7–13.
5. Brink, A.B.A. (1979). Engineering Geology of Southern Africa. Building Publications, Pretoria, Vol. 1.