Doan Ngoc S, Nguyen Thi Hai H. Application of vertical electricalsounding (VES) and Electromagnetic (EM) methods to study shallow geological structures for inspection of gas pipeline foundation . PVJ [Internet]. 2019Aug.30 [cited 2026Jul.15];80:44-9. Available from: https://pvj.vn/index.php/TCDK/article/view/164