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Comment on James J. Heckman, "Instrumental variables: a study of implicit behavioral assumptions used in making program evaluations"
Angrist, Joshua D., (1999)
The relationship between parameters within a latent variable framework
Heckman, James J., (2000)
Identifying the output effects of monetary policy
Cochrane, John H., (1995)
Are local TV markets separate markets?
Ekelund, Robert B., (2000)
Preserving free television? : Some empirical evidence on the efficacy of must-carry
Ford, George S., (2000)
Horizontal concentration and vertical integration in the cable television industry
Ford, George S., (1997)