Lipsey, R. G. (1963). introduction to positive economics (3rd ed.). English Language Book Society.
Dyfyniad Arddull ChicagoLipsey, Richard G. Introduction to Positive Economics. 3rd ed. London: English Language Book Society, 1963.
Dyfyniad MLALipsey, Richard G. Introduction to Positive Economics. 3rd ed. English Language Book Society, 1963.
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