Gaya APA

Wiryono, . et al (1986). North Sumatra Geochemical And Mineral Exploration Project NSGMEP, Mineral Exploration Of The Sijorang Area, Sumatera Utara, Northern Sumatra :A Final report . Bandung: Pusat Sumber Daya Geologi.

Gaya MLA

Wiryono, . et al. "North Sumatra Geochemical And Mineral Exploration Project NSGMEP, Mineral Exploration Of The Sijorang Area, Sumatera Utara, Northern Sumatra :A Final report". Bandung: Pusat Sumber Daya Geologi, 1986. Geokimia.