Sara Martinez-de-morentin Universidad Publica de Navarra   Department of Economics Campus Arrosadia Los Madroños Building Pamplona, Navarra 31006 Spain   sara.martinezdemorentin@unavarra.es   http://www.unavarra.es/pdi/?uid=9060&dato=descripcion&languageId=100000           JEL Areas: J3 : Wages, Compensation, and Labor Costs: General J2 : Demand and Suppply of Labor: General