S. Dlugolinsky, M. Ciglan, and M. Laclavik. Proceedings of the 17th International Conference on Intelligent Engineering Systems, page 197--202. IEEE, (2013)
O. Hassanzadeh, M. Sadoghi, and R. Miller. Proceedings of the International Workshop on Quality in Databases (QDB 2007), page 11-18. Vienna, Austria, (2007)