Barkley, P. W. (1977). Economics: The way we choose. Harcourt Brace Jovanovich.
Dyfyniad Arddull ChicagoBarkley, Paul W. Economics: The Way We Choose. New York: Harcourt Brace Jovanovich, 1977.
Dyfyniad MLABarkley, Paul W. Economics: The Way We Choose. Harcourt Brace Jovanovich, 1977.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.