Gaya APA
M.E., J, K. (1942).
Coal in the East-Indian Achipelago. IIa. The Islands West of Sumatra. .
Bandung:
Direktorat Batubara.
Gaya MLA
M.E., J., KLEINSMIEDE,.
"Coal in the East-Indian Achipelago. IIa. The Islands West of Sumatra.".
Bandung:
Direktorat Batubara,
1942.
Batubara.