Artikel Jurnal
National law Development Agency, 2006
Majalah, Jurnal, Buletin
Aileen Kavanagh, John Oberdiek, editor
Routledge, 2009
Buku Teks
Stone, Richard, author
Cavendish Publishing Limited, 2000
Buku Teks
Mellor, J. Leigh
Teach Yourself Books, 1976
Buku Teks