Citazione APA

Gemological Institute of America & American Gem Society. Gems & gemology. Gemological Institute of America.

Stile di citazione Chicago

Gemological Institute of America e American Gem Society. Gems & Gemology. Santa Monica [etc.]: Gemological Institute of America.

Citazione MLA

Gemological Institute of America e American Gem Society. Gems & Gemology. Gemological Institute of America.