Jago, B.C., and J. Gittins. “The Role of Fluorine in the Crystallization of Niobium and Phosphorus Ores in Carbonatites”. International Kimberlite Conference: Extended Abstracts 5 (February 1, 1991): 193–195. Accessed July 22, 2024. https://ikcabstracts.com/index.php/ikc/article/view/2509.