Allaby, Michael, editor
Oxford University Press, 1992
Buku Referensi
edited by Michael Allaby
Oxford University Press, 1992
Buku Teks
Mayhew, Susan, author
Oxford University Press, 1992
Buku Referensi
editor Joseph G. E.Hopkins
Charles Scribner's Sons, 1964
Buku Referensi
Statt, David A., author
Routledge, 1998
Buku Referensi