FeatureGems & Gemology, Fall 1991, Vol. 27, No. 3

越南红宝石与彩色蓝宝石 (英语)

Robert E. Kane, Shane F. McClure(谢恩·F.·麦克卢尔), Robert C. Kammerling, Nguyen Dang Khoa, Carlo Mora, Saverio Repetto, Nguyen Duc Khai, John I. Koivula(约翰· I.·科伊武拉)