Lennard, John, author
University Press, 2005
Buku Referensi
Cox, C. Barry, author
Edward Arnold, 1979
Buku Teks
Burton, Samuel Holroyd, author
Longman, 1975
Buku Teks
Alexander, Harriet Semmes, 1949-, author
Swallow Press, 1986
Buku Referensi
Spacks, Patricia Meyer, author
Wiley-Blackwell, 2009
Buku Teks