Burridge, Kate, author
Cambridge University Press, 2004
Buku Teks SO
Farrell, Thomas S.C., author
Corwin Press, 2006
Buku Teks
Smith, Charles John, author
Bell and Sons, 1917
Buku Referensi
Lawrence Erlabaum Associates Publisher , 2005
Buku Teks
Yerby, George., author
Routledge, 2016
Buku Teks