Chaveevan Pechsiri Asanee Kawtrakul Mining Causality from Texts for Question Answering System. 1523-1533 2007 90-D IEICE Transactions 10 http://dx.doi.org/10.1093/ietisy/e90-d.10.1523 db/journals/ieicet/ieicet90d.html#PechsiriK07