RitsQA: Ritsumeikan Question Answering System used for QAC-1. - Jun-ichi Fukumoto; Tetsuya Endo; Tatsuhiro Niwa (NTCIR, 2002)

Rits-QA: List Answer Detection and Context Task with Zero Anaphora Handling. - Jun-ichi Fukumoto; Tatsuhiro Niwa; Makoto Itoigawa; Megumi Matsuda (NTCIR, 2004)

YJST at the NTCIR-12 IMine-2 Task. - Yasuaki Yoshida; Hideyuki Maeda; Tatsuhiro Niwa; Sumio Fujita (NTCIR, 2016)