Gemological Institute of America & American Gem Society. Gems & gemology. Gemological Institute of America.
Lua i Stíl Chicago (17ú heag.)Gemological Institute of America agus American Gem Society. Gems & Gemology. Santa Monica [etc.]: Gemological Institute of America.
Lua MLA (8ú heag.)Gemological Institute of America agus American Gem Society. Gems & Gemology. Gemological Institute of America.
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