Cornish, G. P.
Cambridge University Press, 2015
eBooks
James, Francis Edmund Skone
Sweet & Maxwell, 1958
Buku Teks
revised and update by Sandy Norman
Library Association Publishing, 1999
Buku Teks
Norman, Sandy
Library Association Publishing, 1996
Buku Referensi
Marett, Paul
Gower , 1991
Buku Teks