F. Lemmerich, M. Becker, and M. Atzmueller. European Conference on Machine Learning and Knowledge Discovery in Databases, page 277--292. Berlin, Heidelberg, Springer Berlin Heidelberg, (2012)
A. Khan, N. Li, X. Yan, Z. Guan, S. Chakraborty, and S. Tao. Conference, International Conference on Management of Data (SIGMOD/PODS 2011), Athens, Greece - June 12 - 16, 2011, page 901--912. New York, NY, USA, ACM, (2011)