Gaya APA
Energy, M, O, M, A. (1987).
Ombilin Ii Coal Mine Development And Transportation Project .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
Energy, Ministry, Of, Mines, And.
"Ombilin Ii Coal Mine Development And Transportation Project".
Bandung:
Pusat Sumber Daya Geologi,
1987.
Batubara.