1. 1984.Monthly Energy Review73Washington June 1984, Energy Information Administration Report No. DOE/EIA-0035(84106)
2. Lai, R. W. and Gray, M. L. Application of Fluorosurfactants In Selective Flotation of Coal. Process Technology Proceedings 7. Edited by: Attia, Y. A., Moudgil, B. M. and Chandler, S. Elsevier. Interfacial Phenomena in Biotechnology and Materials Processing
3. Yancey, H. F. and Taylor, J. A. 1935.U.S. Bur. Mines Circ. 671429