Gaya APA

Oster, K, E, C, R, C, F, S, M. (2014). Principles of economics: global edition (ed. 11). Boston: Pearson.

Gaya MLA

Oster, Karl, E., Case;, Ray, C., Fair;, Sharon, M.. "Principles of economics: global edition". ed. 11 Boston: Pearson, 2014. Text.