Gaya APA
george, . (1916).
Source of Gipsum in Indonesia their examination and explotation .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
george, .
"Source of Gipsum in Indonesia their examination and explotation".
Bandung:
Pusat Sumber Daya Geologi,
1916.
Bukan Logam.