Oshima, Alice
Pearson Longman, 2006
Buku Teks SO
editors, Junaidi, Elda N. Auliansani, Farah S. Azizah, M. Umar Sadikin
UI Publishing, 2020
Buku Teks
Jordan, R.R.
Collins ELT, 1980
Buku Teks SO
Craswell, Gail
SAGE, 2005
Buku Teks
Leki, Ilona
Cambridge University Press, 1998
Buku Teks SO