1. ISEG‐School of Economics and Management, REM ‐ Research in Economics and Mathematics, CEMAPRE Universidade de Lisboa Lisboa Portugal
2. Polytechnic Institute of Beja, NOVAMATH ‐ Center for Mathematics and Applications, SST New University of Lisbon Lisbon Portugal
3. NOVAMATH ‐ Center for Mathematics and Applications, SST, Polytechnic Institute of Portalegre New University of Lisbon Lisbon Portugal