Laboratory of Operations Research, Department of Economics, University of Thessaly, Volos, Greece
Laboratory of Operations Research, Department of Economics, University of Thessaly, Volos, Greece
Copyright © 2014 George Emm Halkos, George J. Papageorgiou et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.