Thanh Nhieu, Vo, Nguyen Cong Tam, and Chu Van Tho. “REGULARIZED SOLUTIONS OF A CAUCHY PROBLEM FOR THE HELMHOLTZ EQUATION IN AN IRREGULAR STRIP: THE ERROR ESTIMATES”. Science and Technology Development Journal 3, no. 9&10 (October 31, 2000): 9-15. Accessed January 5, 2025. http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3590.