Fernando Ferri Patrizia Grifoni Maurizio Rafanelli The Sketch Recognition and Query Interpretation by GSQL, aGeographical Sketch Query Language. 34-38 2005 conf/IEEEcit/2005 CIT http://doi.ieeecomputersociety.org/10.1109/CIT.2005.190 db/conf/IEEEcit/IEEEcit2005.html#FerriGR05