Thornborrow, Joanna
New York Routledge , 1998
Buku Teks
Fromkin, Victoria A., author
Holt, Rinehart and Winston, 1981
Buku Teks SO
Hazen, Kirk, author
Massachusetts : Wiley Blackwell, 2015
Buku Teks SO
Alfonso, Anthony, author
Sophia University LL Center of Applied Linguistics, 1980
Buku Teks
Argiielles, Alexander, author
Hollym International Corp, 2000
Buku Teks