@article{Mitchell_1991, title={Accessory Rare Earth. Strontium, Barium and Zirconium Minerals in the Benfontein and Wesselton Calcite Kimberlites}, volume={5}, url={https://ikcabstracts.com/index.php/ikc/article/view/2544}, DOI={10.29173/ikc2544}, journal={International Kimberlite Conference: Extended Abstracts}, author={Mitchell, R.H.}, year={1991}, month={Feb.}, pages={292–294} }