1. CEBER, Faculty of Economics University of Coimbra Portugal, Av. Dr. Dias da Silva, 165 Coimbra 3004‐512 Portugal
2. Polytechnic of Coimbra Coimbra Business School Research Centre ISCAC, Coimbra, Portugal, Quinta Agrícola‐ Bencanta Coimbra 3040‐316 Portugal
3. University of Trás‐os Montes and alto Douro, UTAD/CETRAD Quinta dos Prados Vila Real 5000‐801 Portugal