1. Institute for Systems and Computer Engineering, Technology and Science, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal;
2. Booth School of Business, University of Chicago, Chicago, Illinois 60637;
3. Stockholm Business School, Stockholm University, SE-106 91 Stockholm, Sweden;
4. Center for Research and Innovation in Business Sciences and Information Systems, ESTG, Polytechnic of Porto, 4610-156 Felgueiras, Portugal