Littlewood, William T.
Cambridge University Press, 1994
Buku Teks
Mitchell, Rosamond
Routledge, 2004
Buku Teks
Mitchell, Rosamond
Arnold, 1998
Buku Teks SO
Cook, Vivian
Edward Arnold, 2001
Buku Teks
Allen, Edward David, 1923-
Harcourt Brace Jovanovich, c1977
Buku Teks