Gaya APA

OPPENOORTH, I, W., ZWIERZYCKI, D, J. (1918). Geomorphological And Tectonical Observations As A Contribution To the Explanation of the Land-Forms of North Sumatra . Bandung: TISITUTYOSAZYO.

Gaya MLA

OPPENOORTH, Ir., W.F.F.., ZWIERZYCKI, Dr., J. "Geomorphological And Tectonical Observations As A Contribution To the Explanation of the Land-Forms of North Sumatra". Bandung: TISITUTYOSAZYO, 1918. .