Waddington, P.A.J
Avebury, 1993
Buku Teks
Jones, Marjorie, author
Barry Rose Publishers, 1974
Buku Teks
editor, Daniel Greenberg
Sweet & Maxwell, 2017
Buku Teks
Heidensohn, Frances, author
Macmillan, 1989
Buku Teks
Mays, John Barrons
Longman, 1970
Buku Teks