Allan Kolker Robert B. Finkelman K.C. Kolb Stanley J. Mroczkowski S.S. Crowley H. E. Belkin J. H. Bullock Jr. J. M. Motooka Curtis A. Palmer 1997 <p>No abstract available.</p> application/pdf 10.3133/ofr97732 en U.S. Geological Survey Modes of occurrence of trace elements in samples from a coal cleaning plant reports