Beom Suk Jin, Sang Min Ko, Jae Seung Mun, Yong Gu Ji. A Study for Usability Risk Level in Physical User Interface of Mobile Phone. In Nuray M. Aykin, editor, Usability and Internationalization. HCI and Culture, Second International Conference on Usability and Internationalization, UI-HCII 2007, Held as Part of HCI International 2007, Beijing, China, July 22-27, 2007, Proceedings, Part I. Volume 4559 of Lecture Notes in Computer Science, pages 327-335, Springer, 2007. [doi]