Zartman, R.E., S.H. Richardson, J.J. Gurney, and R.O. Moore. 1998. “U-Th-Pb Ages of Megacrystic Zircon from the Monastery Kimberlite, Free State, South Africa”. International Kimberlite Conference: Extended Abstracts 7 (1):989-91. https://doi.org/10.29173/ikc2956.