INFORMATION PROCESSING & MANAGEMENT, vol. 43, no. 2, page. 302 - 314, 2007-03
LECTURE NOTES IN COMPUTER SCIENCE, vol. 3689, page. 274 - 287, 2005-01
LECTURE NOTES IN COMPUTER SCIENCE, vol. 3248, page. 566 - 575, 2005-01
LECTURE NOTES IN COMPUTER SCIENCE, vol. 3689, page. 288 - 298, 2005-01
IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, vol. E89-D, no. 2, page. 837 - 846, 2006-02