Casteleyn, Mary
Bowker Saur , 1993
Buku Teks SO
consultant editor, Michael Armstrong
AP Information Services, 1997
Buku Referensi
Dale, Margaret
Kogan Page Limited, 2003
Buku Teks
edited by Margaret Oldroyd
Library Association , 1997
Buku Teks SO
Jordan, Peter
Ashgate, 2002
Buku Teks SO