McIver, J.R., and John Ferguson. “Kimberlitic, Melilititic, Trachytic and Carbonatitic Eruptives at Saltpetre Kop, Sutherland, South Africa”. International Kimberlite Conference: Extended Abstracts 2, no. 1 (September 12, 1977): 212–214. Accessed February 13, 2026. https://journals.library.ualberta.ca/ikcabstracts.com/index.php/ikc/article/view/995.