TY  - BOOK
AU  - Zegeer, David A.,
AU  - Crickmer, Douglas F.,
TI  - Elements of practical coal mining
SN  - 0895202700
AV  - TN802 E45 1981
PY  - 1981///
CY  - New York
PB  - American institute of mining, metallurgical, and petroleum engineers
KW  - Huella
KW  - Minas y mineria
ER  -