1. Rare earth elements: their importance in understanding soil genesis;Aide;ISRN Soil Sci.,2012
2. Investigations of the Fire Clay coal bed, southeastern Kentucky, in the vicinity of sandstone washouts;Andrews;Int. J. Coal Geol.,1994
3. Oxidation Zone of Coalfields as a Promising Source of Noble and Rare Metals: A Case of Coalfields in Central Asia. Problems and Outlook of Development of Mineral Resources and Fuel-Energetic Enterprises of Siberia, Tomsk Polytechnic Univ., Tomsk;Arbuzov,2007
4. Bragg, L.J., Oman, J.K., Tewalt, S.J., Oman, C.L., Rega, N.H., Washington, P.M., Finkelman, R.B., 1998. U.S. Geological Survey coal quality (COALQUAL) database: version 2.0. U.S. Geol. Surv. Open File Rep. 97–134, (CD-ROM).
5. Statistical Analysis of Coal Quality Parameters for the Pennsylvanian System Bituminous Coals in Eastern Kentucky, USA (Unpublished PhD thesis);Collins,1993