Wharton, Edith, author
Everyman, 1993
Buku Teks
Kirby, David K., author
Gale Research, 1975
Buku Referensi
Greene, Richard
Red & White Pub., 2010
Buku Teks
edited by H.V. Hodson
Longman, 1984
Buku Referensi
Drake, Ellen, author
Elsevier Saunder, 2012
Buku Teks