The Program Tutoring Text Model. - Hiroyuki Ohnuma; Toyohide Watanabe (Intelligent Tutoring Systems, 1996)

Oki QA System for QAC-1. - Atsushi Ikeno; Hiroyuki Ohnuma (NTCIR, 2002)

Oki QA System for QAC-2. - Masachika Fuchigami; Hiroyuki Ohnuma; Atsushi Ikeno (NTCIR, 2004)