Diamond, Arthur Sigismund
Methuen, 1959
Buku Teks SO
Noriko Takada
Macmillan, 1995
Buku Teks
Frellesvig, Bjark
Cambridge University Press, 2010
Buku Teks
Chomsky, Noam
Praeger , 1986
Buku Teks
Alfonso, Anthony
Sophia University LL Center of Applied Linguistics, 1980
Buku Teks