N Semantic Classes are Harder than Two Ben Carterette author Rosie Jones author Wiley Greiner author Cory Barr author 2006-07 text Proceedings of the COLING/ACL 2006 Main Conference Poster Sessions Association for Computational Linguistics Sydney, Australia conference publication carterette-etal-2006-n https://aclanthology.org/P06-2007/ 2006-07 49 56