Open University Press, 1998
Buku Teks
Edited, Suzanne Ferriss, Mallory Young
Routledge, 2006
Buku Teks
Talitha Sal Shabilla
2018
UI - Skripsi (Membership)
Alexander, Linda Lewis
Jones & Bartlett Learning, 2014
Buku Teks
Williams, Norma
Tiger Books International, 1990
Buku Referensi