Mikhail Alexandrov, Alexander Gelbukh, George Lozovoi. Chi-square Classifier for Document Categorization. Proc. CICLing-2001, 2nd International Conference on Intelligent Text Processing and Computational Linguistics, February 1824, 2001, Mexico City. Lecture Notes in Computer Science N 2004, Springer-Verlag, pp. 455-457; www.Gelbukh.com/CV/Publications/2001/CICLing-2001-Chi-Square.htm

Please see here.