Graf, B. (2001). Gems: The world's greatest treasures and their stories. Prestel.
Chicago (17e ed.) BronvermeldingGraf, Bernhard. Gems: The World's Greatest Treasures and Their Stories. Munich: Prestel, 2001.
MLA (9e ed.) BronvermeldingGraf, Bernhard. Gems: The World's Greatest Treasures and Their Stories. Prestel, 2001.
Let op: Deze citaties zijn niet altijd 100% accuraat.