APA (7e ed.) Bronvermelding

Graf, B. (2001). Gems: The world's greatest treasures and their stories. Prestel.

Chicago (17e ed.) Bronvermelding

Graf, Bernhard. Gems: The World's Greatest Treasures and Their Stories. Munich: Prestel, 2001.

MLA (9e ed.) Bronvermelding

Graf, Bernhard. Gems: The World's Greatest Treasures and Their Stories. Prestel, 2001.