Gaya APA
EN, H, K, P. (1991).
Dbase III +, FoxBase+Multi User (Local Area Network) (Ed. II).
New York:
Pusat Sumber Daya Geologi.
Gaya MLA
EN, Harianto, K,, Pangestu.
"Dbase III +, FoxBase+Multi User (Local Area Network)".
Ed. II
New York:
Pusat Sumber Daya Geologi,
1991.
Textbook.