Giacomini, M. , Bertone, S. , Mansi, C. , Dulbecco, P. , Savarino, V.. "Idiopathic Constipation can be Subdivided in Clinical Subtypes: Data Mining by Cluster Analysis on a Population based Study". World Academy of Science, Engineering and Technology, Open Science Index 18, International Journal of Medical and Health Sciences, (2008), 2(6), 207 - 213.