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The interdependence of quality variations, selling effort and price
Brems, Hans, (1948)
Management, marketing, and public policy : three keynote talks
Eppert, Ray R., (1963)
Die Stellung der Werbung in der modernen Absatzwirtschaft
Greiser, Franz, (1957)
The economic status of the aged
Steiner, Peter O., (1957)
Microeconomics
Lipsey, Richard, (1979)
Macroeconomics