Epstein, E.L.
Methuen, 1978
Buku Teks
Hazen, Kirk
Massachusetts : Wiley Blackwell, 2015
Buku Teks
Fromkin, Victoria A.
Holt, Rinehart and Winston, 1981
Buku Teks
Alfonso, Anthony
Sophia University LL Center of Applied Linguistics, 1980
Buku Teks
Argiielles, Alexander
Hollym International Corp, 2000
Buku Teks