Forst: A Challenge to the NTCIR-15 QA Lab-PoliInfo-2 Task. - Hiromu Onogi; Kiichi Kondo; Younghun Lim; Xinnan Shen; Madoka Ishioroshi; Hideyuki Shibuki; Tatsunori Mori; Noriko Kando (NTCIR, 2020)