Dyfyniad APA

O'Sullivan, A., & Sheffrin, S. M. (2006). Economics: Principles and tools (4th ed.). Pearson/ Prentice Hall.

Dyfyniad Arddull Chicago

O'Sullivan, Arthur, and Steven M. Sheffrin. Economics: Principles and Tools. 4th ed. Upper Saddle River, NJ: Pearson/ Prentice Hall, 2006.

Dyfyniad MLA

O'Sullivan, Arthur, and Steven M. Sheffrin. Economics: Principles and Tools. 4th ed. Pearson/ Prentice Hall, 2006.

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