Ohta, Amy Snyder, author
Lawrence Erlbaum Associates Publ, 2001
Buku Teks
Littlewood, William T.
Cambridge University Press , 1994
Buku Teks
Mitchell, Rosamond, author
Routledge, 2004
Buku Teks
Mitchell, Rosamond, author
Arnold, 1998
Buku Teks SO
Cook, Vivian, author
ARNOLD, 2001
Buku Teks