Learning Based Approaches for Vietnamese Question Classification Using Keywords Extraction from the Web Dang Hai Tran author Cuong Xuan Chu author Son Bao Pham author Minh Le Nguyen author 2013-10 text Proceedings of the Sixth International Joint Conference on Natural Language Processing Ruslan Mitkov editor Jong C Park editor Asian Federation of Natural Language Processing Nagoya, Japan conference publication tran-etal-2013-learning https://aclanthology.org/I13-1088/ 2013-10 740 746