Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

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

Cita MLA (8a ed.)

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