Gaya APA
Geologi, P, S, D. (2001).
Clean Coal Technology Demonstration Program: Program Update 2000 .
Bandung:
U.S. department of Energy.
Gaya MLA
Geologi, Pusat, Sumber, Daya.
"Clean Coal Technology Demonstration Program: Program Update 2000".
Bandung:
U.S. department of Energy,
2001.
Batubara.