Topic-Driven Multi-Document Summarization with Encyclopedic Knowledge and Spreading Activation Vivi Nastase author 2008-10 text Proceedings of the 2008 Conference on Empirical Methods in Natural Language Processing Mirella Lapata editor Hwee Tou Ng editor Association for Computational Linguistics Honolulu, Hawaii conference publication nastase-2008-topic https://aclanthology.org/D08-1080/ 2008-10 763 772