Devina Gary Oktiana, author
2017
UI - Skripsi (Membership)
Davies, Jack, author
West Publishing, 1975
Buku Teks
Maddex, Robert L., author
London: Routledge, 1995,
Buku Referensi
Keefe, William J., author
Prentice-Hall, 1994
Buku Teks
Alissa Shebila, author
Universitas Indonesia, 2015
UI - Skripsi (Membership)