Gaya APA

Sumartono, ., A, I. (1988). Mineral Exploration of The Tinjoan Area, Sumatra Utara, Northern Sumatra . Bandung: Pusat Sumber Daya Geologi.

Gaya MLA

Sumartono, ., A, Iskandar. "Mineral Exploration of The Tinjoan Area, Sumatra Utara, Northern Sumatra". Bandung: Pusat Sumber Daya Geologi, 1988. Geokimia.