TY  - RPRT
TI  - Semi-quantitative determination of the modes of occurrence of elements in coal: Results from an international round robin project
AU  - Jason C. Willett
AU  - Robert B. Finkelman
AU  - Stanley J. Mroczkowski
AU  - Curtis A. Palmer
AU  - Allan Kolker
PY  - 2000
DO  - 10.3133/ofr00414
UR  - https://pubs.usgs.gov/publication/ofr00414
ID  - ofr00414
ER  -