Lorenz, V., et al. “Volcanology of the Diatreme-Rich Carbonatitic Gross Brukkaros Volcanic Field and of the Nearby Gibeon Kimberlite Province, Namibia”. International Kimberlite Conference: Extended Abstracts, vol. 6, no. 1, Sept. 1995, pp. 333-5, doi:10.29173/ikc1883.