Ruby and Sapphire from the Tan Huong-Truc Lau Area, Yen Bai...
nguyen ngoc kHoi, SuTTHiraT, c., duong anH Tuan, nguyen Van nam, nguyen THi minH THuyeT & nguy TuyeT nHung (2011): Ruby and Sapphire from the Tan Huong-Truc Lau Area, Yen Bai Province, Northern Vietnam. - Gems & Gemol. 47 (3): 182 -195....