1. Public Debt, Contingent Liabilities, and 'Debt Tolerance': The Case of Colombia", paper presented at the workshop Fiscal Indicators, organized by Banca d'Italia in Perugia;S Clavijo;Social Security Reform in Colombia: Implicit Taxes, Deathweight Losses, and Sustainability,2003
2. La reforma al sistema de salud: grandes preocupaciones;FEDESARROLLO,2005