1. Research on Economics, Management and Information Technologies, REMIT, Portucalense University, Rua Dr. António Bernardino Almeida, 541-619, P 4200-072 Porto, Portugal
2. Instituto Superior Miguel Torga, 3000-132 Coimbra, Portugal
3. NECE-UBI—Research Unit in Business Sciences, University of Beira Interior, 6201-001 Covilhã, Portugal