Gaya APA
ES., D. (1963).
THE COAL DEPOSITS OF THE SOUTH-WEST COAST OF SUMATRA .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
ES., DR.IR.L.J.C.VAN.
"THE COAL DEPOSITS OF THE SOUTH-WEST COAST OF SUMATRA".
Bandung:
Pusat Sumber Daya Geologi,
1963.
Batubara.