Vu, Doan. “Gemological Characteristics of Sapphire from Hong Liem, Ham Thuan Bac District, Binh Thuan Province, Viet Nam”. Science & Technology Development Journal: Natural Sciences 4, no. 1 (April 10, 2020): 412-420. Accessed April 26, 2024. http://stdjns.scienceandtechnology.com.vn/index.php/stdjns/article/view/594.