Rennison, Nick, author
Routledge, 2005
Buku Teks
edited by L. S. Dembo and Cyrena N. Pondrom
University of Wisconsin Press, 1972
Buku Teks
edited by Peter Childs, Mike Storry
Routledge, 1999
Buku Referensi
Robinson, Alan, author
Macmillan, 1988
Buku Teks
Macmillan, 1994
Buku Teks