revised and updated by Sandy Norman
Library Association Publishing, 1999
Buku Teks
Library Association , 2000
Buku Teks
Williams, Gareth, author
PSI, [date of publication not identified]
Buku Teks
Hobsons Pub.,, 1987
Buku Referensi
Norman, Sandy, author
Library Association Publishing, 1996
Buku Referensi