Gaya APA
Geologi, P, S, D. (1981).
Stratigraphy And Depositional Environment Of The Ombilin II Area .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
Geologi, Pusat, Sumber, Daya.
"Stratigraphy And Depositional Environment Of The Ombilin II Area".
Bandung:
Pusat Sumber Daya Geologi,
1981.
Batubara.