Gaya APA
Rohland, W. (1956).
General Working Material For The Work to be Carried Out in Indonesia. "Wedexro" April 1956 .
Jakarta:
Pusat Sumber Daya Geologi.
Gaya MLA
Rohland, W..
"General Working Material For The Work to be Carried Out in Indonesia. "Wedexro" April 1956".
Jakarta:
Pusat Sumber Daya Geologi,
1956.
Batubara.