1. Finkelman, R. B., Modes of occurrence of trace elements in coal. University of Maryland. Ph.D. dissertation, 301 p., 1980.
2. Finkelman, R. B., and Stanton, R. W., Fuel, v. 57, p. 763, 1978.
3. Finkelman, R. B., SEM 1978 /1, p. 143, 1978.
4. Most mineralogical identifications have been confirmed by optical characterization or by X-ray diffraction analysis.
5. Minkin, J. A., Finkelman, R. B., Thompson, C. L., Cecil, C. B., Stanton, R. W., and Chao, E. C. T., Ninth International Carboniferous Congress, Compte Rendu, in press.