Gaya APA

PH.D., K, H, &, M, L, J. (2008). Gemstones: A Complete Reference Color Precious and Semiprecious Stones of The World . Singapore: Page One Publishing Pte Ltd..

Gaya MLA

PH.D., Karen, Hurrel, &, Marry, L., Johnson,. "Gemstones: A Complete Reference Color Precious and Semiprecious Stones of The World". Singapore: Page One Publishing Pte Ltd., 2008. Text.