Byrns, R. T., & Stone, G. W. (1992). Economics (5th ed.). HarperCollins College Pub..
Dyfyniad Arddull ChicagoByrns, Ralph T., and Gerald W. Stone. Economics. 5th ed. New York: HarperCollins College Pub., 1992.
Dyfyniad MLAByrns, Ralph T., and Gerald W. Stone. Economics. 5th ed. HarperCollins College Pub., 1992.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.