Dani Ronnie M, author
Hikmah, 2006
Buku Teks
Nunan, David, author
Pearson Education, 2000
Buku Referensi
Musser, Gary L., author
John Wiley & Sons, 2006
Buku Teks
Thornburn, Scott, 1950-, author
Cambridge University Press, 2017
Buku Teks
Krause, Eugene F.
Prentice-Hall, 1978
Buku Teks