APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (8th ed.) Citation

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