There are four files:
match.ado 
    this is the basic ado file for the matching program
lalonde_exper_v7_04feb2.do
    this is a sample program that calculates a number
    of matching estimators and illustrates the various options
    The various options are described in more detail in
    the paper ``implementing matching estimators for average
    treatment effects in stata'', available on
    /users/imbens/wp.shtml
lalonde_exper_v7_04feb2.smcl
    this is the smcl file with the output from the do-file
    lalonde_exper_v7_04feb2.do
lalonde_exper.dta
    stata data file with the data used in lalonde_exper_v7_04feb2.do