Extracting Exact Answers to Questions Based on Structural Links Wei Li author Rohini K Srihari author Xiaoge Li author M Srikanth author Xiuhong Zhang author Cheng Niu author 2002 text COLING-02: Multilingual Summarization and Question Answering conference publication li-etal-2002-extracting https://aclanthology.org/W02-1905/ 2002