Gaya APA
Ritchie, J, A. (1977).
Bentonite Project New Zealand Bilateral Assistance Programme to Indonesia .
Bandung:
Direktorat Sumber Daya Mineral.
Gaya MLA
Ritchie, John, A.
"Bentonite Project New Zealand Bilateral Assistance Programme to Indonesia".
Bandung:
Direktorat Sumber Daya Mineral,
1977.
Umum.