Dung, Tran Trung, et al. “An XFEM Based Kinematic Limit Analysis Formulation for Plane Strain Cracked Structures Using SOCP”. HO CHI MINH CITY OPEN UNIVERSITY JOURNAL OF SCIENCE - ENGINEERING AND TECHNOLOGY, vol. 3, no. 1, Aug. 2013, pp. 50-58, https://journalofscience.ou.edu.vn/index.php/tech-en/article/view/402.