Chang, Hangbae, Kyung Kyu Kim, and Yeongdeok Kim. “The Development of Security System for Sharing CAD Drawings in U-Environment”. Computing and Informatics 27, no. 5 (January 26, 2012): 731–741. Accessed November 23, 2024. http://147.213.75.17/ojs/index.php/cai/article/view/212.