Gaya APA
Heckman, James J.. ().
Sample selection bias as a specification error .
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Gaya Chicago
Heckman, James J..
Sample selection bias as a specification error.
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Text.
Gaya MLA
Heckman, James J..
Sample selection bias as a specification error.
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Text.
Gaya Turabian
Heckman, James J..
Sample selection bias as a specification error.
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