Maria Fraga Oliveira Martins, "Parametric and Semiparametric Estimation
of Sample Selection Models: An Empirical Application to the Female
Labour Force in Portugal", Journal of Applied Econometrics, Vol. 16, 
No. 1, 2001, pp. 23-40.

The files described below are all zipped in martins.zip.

There is one data set, martins.data.  This 63 KB data file, which is in DOS
format, is organized in the following way. There are seven columns,
corresponding to seven variables, and 2339 observations.

	First column: binary variable, that is equal to 1 if woman
	participates and 0, otherwise.

	Second column: number of children younger than 18 living in the
	family.

	Third column: number of children younger than 3 .

	Fourth column: women's age.  

	Column five: log of women's hourly wage rate (measured in escudos).

	Column six: women's educational level, measured in years of
	schooling.

	Column seven: log of the husband's monthly wage (measured in
	escudos).

The data set is a sample from Portuguese Employment Survey, from the
interview year 1991, and has been provided by the Portuguese National
Institute of Statistics (INE).

There are three program files: empp.martins.prg, int.martins and
testsemi.martins. 

empp.martins.prg is a Gaussx program file to compute semiparametric
(Klein-Spady) estimates.

int.martins.xpl is an Xplore program file to compute Horowitz uniform
confidence bands.

testsemi.martins.xpl is an Xplore program file to compute the Horowitz and
Härdle test.