PHÁI, Vũ Văn; 						QUIN, Andrew.
 Vài nét khái quát về địa hình Karst ở Lạng Sơn.
<strong>VNU Journal of Science: Natural Sciences and Technology</strong>, [S.l.], v. 9, n. 7, sep. 1993.
ISSN 2588-1140.
Available at: &lt;<a href="https://js.vnu.edu.vn/NST/article/view/4390" target="_new">https://js.vnu.edu.vn/NST/article/view/4390</a>&gt;. Date accessed: 18 dec. 2024.