Georgios Sigletos Georgios Paliouras Constantine D. Spyropoulos Michael Hatzopoulos Combining Information Extraction Systems Using Voting and Stacked Generalization. 1751-1782 2005 6 Journal of Machine Learning Research http://www.jmlr.org/papers/v6/sigletos05a.html db/journals/jmlr/jmlr6.html#SigletosPSH05