1. Democracy Research Unit, Political Science Department, College of Law and Public Administration, University of Salamanca, Salamanca, Spain
2. Media Effects Research Lab, Media Studies Department, Donald P. Bellisario College of Communications, Pennsylvania State University, University Park, PA, USA
3. Facultad de Comunicación y Letras, Universidad Diego Portales, Santiago, Chile
4. Department of Communication, Universidad Carlos III, Madrid, Spain