Whitla, William, author
Wiley-Blackwell, 2010
Buku Referensi
Jackson, J.R. de J.
Routlege, 1989
Buku Teks
Moi, Toril, author
Routlege, 1988
Buku Teks
Garry L. Hagberg and Walter Jost, editors
Wiley Balckwell, 2010
Buku Teks
Mayfield Publishing Company , 1994
Buku Teks