Gaya APA
Geologi, P, S, D. (1994).
Interim Report On Ombilin III Coal The Detailed Exploration .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
Geologi, Pusat, Sumber, Daya.
"Interim Report On Ombilin III Coal The Detailed Exploration".
Bandung:
Pusat Sumber Daya Geologi,
1994.
Batubara.