Sandler, Wendy
Cambridge University Press, 2006
Buku Teks
Hawkins, John A.
Basil Black Well , 1988
Buku Teks
Cambridge University Press, 2006
eBooks
Holt, Rinehart and Winston, 1968
Buku Teks
Greenberg, Joseph H. (Joseph Harold), 1915-2001
Mounton, 1976
Buku Teks