Ferber, R., & Verdoorn, P. (1962). Research methods in economics and business. Macmillan company.
Dyfyniad Arddull ChicagoFerber, Robert, and P.J Verdoorn. Research Methods in Economics and Business. London: Macmillan company, 1962.
Dyfyniad MLAFerber, Robert, and P.J Verdoorn. Research Methods in Economics and Business. Macmillan company, 1962.
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