COMPUTER SYSTEMS SCIENCE AND ENGINEERING, vol. 21, no. 6, page. 395 - 404, 2006-11
IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING, vol. 18, no. 2, page. 245 - 260, 2006-02
JOURNAL OF SYSTEMS AND SOFTWARE, vol. 79, no. 2, page. 180 - 190, 2006-02