W. G. Davenport (1999). "Copper extraction from the 60s into the 21st century". Trong G. A. Eltringham; N. L. Piret; M. Sahoo (biên tập). Proceedings of the Copper 99–Cobre 99 International Conference. Quyển I—Plenary Lectures/Movement of Copper and Industry Outlook/Copper Applications and Fabrication. Warrendale, Pennsylvania: The Minerals, Metals and Materials Society. tr. 55–79. OCLC42774618.
