Joyce Y. Chai Shimei Pan Michelle X. Zhou Keith Houck Context-Based Multimodal Input Understanding in Conversational Systems. 87-92 2002 conf/icmi/2002 ICMI http://doi.ieeecomputersociety.org/10.1109/ICMI.2002.1166974 db/conf/icmi/icmi2002.html#ChaiPZH02