Gaya APA
Chaffey, D. et al (2019).
Digital Marketing: Strategy, Implementation and Practice (ed. tujuh).
United Kingdom:
Pearson Education Limited.
Gaya MLA
Chaffey, Dave. et al.
"Digital Marketing: Strategy, Implementation and Practice".
ed. tujuh
United Kingdom:
Pearson Education Limited,
2019.
BUKU.