C. Schmitz, A. Hotho, R. Jäschke, and G. Stumme. Data Science and Classification: Proc. of the 10th IFCS Conf., page 261--270. Berlin, Heidelberg, Springer, (2006)
R. Agrawal, and R. Srikant. VLDB '94: Proceedings of the 20th International Conference on Very Large Data Bases, page 487--499. San Francisco, CA, USA, Morgan Kaufmann Publishers Inc., (1994)