Nguyen Thi Thao, Mai Thuy Dung, Pham Vu Loc, Nguyen Thi Kim Ha, Pham Ngoc Diep, and Pierre Darriulat. “The 50 Cm Telescope of Hoa Lac Observatory: An Introduction”. Vietnam Journal of Science, Technology and Engineering 61, no. 4 (December 15, 2019): 14-28. Accessed July 16, 2026. https://vietnamscience.vjst.vn/index.php/vjste/article/view/150.