Cornish, G. P.
Cambridge University Press, 2015
eBooks
James, Francis Edmund Skone
Sweet & Maxwell, 1958
Buku Teks
Norman, Sandy
Library Association Publishing, 1996
Buku Referensi
revised and update by Sandy Norman
Library Association Publishing, 1999
Buku Teks SO
revised and updated by Sandy Norman
Library Association Publishing, 1999
Buku Teks SO