Huong, Le Thi Thu, Tobias Haeger, and The-Long Phan. “Study of Impurity in Blue Spinel from the Luc Yen Mining Area, Yen Bai Province, Vietnam”. Vietnam Journal of Earth Sciences 40, no. 1 (March 15, 2018): 47–55. Accessed April 20, 2024. https://vjs.ac.vn/index.php/jse/article/view/10915.