@article {BonchiGLOPT09, title = {A constraint-based querying system for exploratory pattern discovery}, journal = {Inf. Syst.}, volume = {34}, number = {1}, year = {2009}, pages = {3-27}, author = {Francesco Bonchi and Fosca Giannotti and Claudio Lucchese and Salvatore Orlando and Raffaele Perego and Roberto Trasarti} }