Duong, Nguyen Thuy, Huong, Nguyen Thi Nhu, Huong, Nguyen Van, AND Phuong, Ta Hoa. " Assessment of Geoheritage of Geosites in Dong Van District, Ha Giang Province" VNU Journal of Science: Earth and Environmental Sciences [Online], Volume 35 Number 1 (26 March 2019)