Affiliation: | aInstitute of Information Systems, Vienna University of Technology, Favoritenstraße 9-11, A-1040 Vienna, Austria;bFaculty of Engineering and Natural Sciences, Sabancı University, Orhanli, Tuzla, Istanbul 34956, Turkey;cDepartment of Mathematics, University of Calabria, Via P. Bucci, cubo 30b, 87036 Rende (CS), Italy |