1. Higher Institute for Accountancy and Administration of the University of Aveiro R. Associação Humanitária dos Bombeiros Voluntários de Aveiro Aveiro 3810‐500 Portugal
2. Centre for Business and Economics Research (CeBER) Faculty of Economics, University of Coimbra Av. Dias da Silva, 165 Coimbra 3004–512 Portugal
3. Faculty of Economics, University of Coimbra Av. Dias da Silva, 165 Coimbra 3004–512 Portugal
4. Institute for Systems Engineering and Computers at Coimbra Rua Antero de Quental, N°199 Coimbra 3000–033 Portugal