1. The occurrence of elemental sulphur in coals
2. Huggins , F.E. , Mitra , S. , Vaidya , S. , Taghiei , M.M. , Lu , F. , Shah , N. , and Huffman , G.P. 1991 . The Quantitative Determination of all Major Inorganic and Organic Sulfur Forms in Coal from XAFS Spectroscopy Method and Applications, Proceeding, 4th, International Conference on Processing and Utilization of High Sulfur Coals , Idaho Falls , ID , August 26-30, 1991 .
3. Aromatic sulfur compounds other than condensed thiophenes in fossil fuels: enrichment and identification
4. PROCESS ENGINEERING STUDIES OF THE PERCHLOROETHYLENE COAL CLEANING PROCESS
5. Lee , S. , Fullerton , K.L. , and Vishnubhatt , P. 1991 b . Updates of Perchloroethylene Coal Extraction Process Development, Proceedings Sixteenth Annual EPRI Conference on Fuel Science and Conversion , May , 1991 , in press .