Gaya APA
Management. (2014).
UK:
Pearson Education Limited.
Gaya Chicago
Management.
.
UK:
Pearson Education Limited,
2014.
Buku.
Gaya MLA
Management.
.
UK:
Pearson Education Limited,
2014.
Buku.
Gaya Turabian
Management.
UK:
Pearson Education Limited,
2014.
Buku.