Dyfyniad APA

Samuelson, P. A., & Nordhaus, W. D. (2005). Economics (18th ed.). McGraw-Hill/Irwin.

Dyfyniad Arddull Chicago

Samuelson, Paul A., and William D. Nordhaus. Economics. 18th ed. Boston: McGraw-Hill/Irwin, 2005.

Dyfyniad MLA

Samuelson, Paul A., and William D. Nordhaus. Economics. 18th ed. McGraw-Hill/Irwin, 2005.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.