1. Costo Fiscal e Impacto Macroeconómico de la Reforma Pensión Colombiana;Ayala;paper presented by Foro Secretaría de Hacienda de México and World Bank,1997
2. Evolución Reciente y Futuro del Sistema General de Pensiones en Colombia;Ocampo;paper presented by the ministy of finance,1996
3. Pension Regimes and Saving;Mackenzie;IMF Occasional Paper No. 153,1997
4. Colombia's pension reform
5. A Survey of Economic Reforms and Macroeconomic Performance: A Comparative Study of Chile and Colombia 1970–95;Clavijo;IMF Working Paper 95/139,1995