Gaya APA

Energy, M, O, M, A., Mines, D, G, O. (1985). Ombilin II Coal Mine Development And Transportation Project Coal Quality Testing Report . United State: Direktorat Sumber Daya Mineral.

Gaya MLA

Energy, Ministry, Of, Mines, And., Mines, Directorate, General, Of. "Ombilin II Coal Mine Development And Transportation Project Coal Quality Testing Report". United State: Direktorat Sumber Daya Mineral, 1985. Batubara.