1. Kuuskraa V, Stevens S, Van Leeuwen T, Moodhe, K. World shale gas resources: An initial assessment. Prepared for: United States Energy Information Administration, 2011. World Shale Gas Resources: An Intital Assessment of 14 Regions Outside the United States. Available at http://www.eia.doe.gov/analysis/studies/worldshalegas.
2. Decker J ,Marot J. Investigation of hydraulic fracturing in the Karoo of South Africa. Annexure A, Resource Assessment , Pertoluem Agency SA 2012. Available at: http://www.dmr.gov.za/publications/viewdownload/182/854.html.
3. Catuneanu O, Wopfner H, Eriksson PG, Cairncross B, Rubidge BS, Smith RMH. The Karoo basins of south-central Africa. Journal of African Earth Sciences2005;43:211-253.
4. Tankard A, Welsink H, Aukes P, Newton R, Stattker E. Geodynamic interpretation of the Cape and the Karoo basins, South Africa. Phanerozoic Passive Marigins, Cratonic Basins and Global Tectonics Maps. USA & UK: Elsevier 2012. p869.
5. Deep crustal profile across the southern Karoo Basin and Beattie magnetic anomaly;Lindeque;South Africa: An integrated interpretation with tectonic implications. South African Journal of Geology,2011