Cross-Task Knowledge-Constrained Self Training Hal Daumé III 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 daume-iii-2008-cross https://aclanthology.org/D08-1071/ 2008-10 680 688