TY  - BOOK
CN  - QE75
CN  - QE75
CN  - TN805
CY  - Washington :
DA  - 1976.
ID  - 8200
KW  - Coal
N1  - "Definitions of coal resource classification terms used by the U.S. Bureau of Mines and U.S. Geological Survey."
PB  - U.S. Govt. Print. Off.,
PP  - Washington :
PY  - 1976.
T1  - Coal resource classification system of the U.S. Bureau of Mines and U.S. Geological Survey :a report /
TI  - Coal resource classification system of the U.S. Bureau of Mines and U.S. Geological Survey :a report /
ER  -