Gaya APA

Principles of economics / Karl E. Case ; Ray C. Fair ; Sharon M. Oster. (2017). Harlow, UK: Pearson Education, c.

Gaya MLA

Principles of economics / Karl E. Case ; Ray C. Fair ; Sharon M. Oster. 12th ed.. Harlow, UK: Pearson Education, c, 2017. Buku Wajib.