Dmitri Roussinov Yin Ding Jose Antonio Robles-Flores Experiments with Web QA System and TREC 2004 Questions. 2004 TREC http://trec.nist.gov/pubs/trec13/papers/arizonau.qa.pdf conf/trec/2004 db/conf/trec/trec2004.html#RoussinovDR04