Delgado, Miguel A.Robinson, Peter M.2009-05-082009-05-081992Journal of Economic Surveys. 1992, vol. 6, nº 3, p. 201-2490950-0804https://hdl.handle.net/10016/2357application/pdfeng© BlackwellNonparametric and Semiparametric Methods for Economic Researchresearch articleEconomía10.1111/j.1467-6419.1992.tb00151.xopen access2013249Journal of Economic Surveys6