Gaya APA
Principles of Economics. (2017).
Harlow, UK:
Pearson.
Gaya Chicago
Principles of Economics.
12.
Harlow, UK:
Pearson,
2017.
Buku.
Gaya MLA
Principles of Economics.
12.
Harlow, UK:
Pearson,
2017.
Buku.
Gaya Turabian
Principles of Economics.
Harlow, UK:
Pearson,
2017.
Buku.