Gemological Institute of America & American Gem Society. Gems & gemology. Gemological Institute of America.
Chicago Style (17th ed.) CitationGemological Institute of America and American Gem Society. Gems & Gemology. Santa Monica [etc.]: Gemological Institute of America.
MLA (8th ed.) CitationGemological Institute of America and American Gem Society. Gems & Gemology. Gemological Institute of America.
Warning: These citations may not always be 100% accurate.