Chambers, Raymond J., author
The Law Book Co., 1967
Buku Teks
Courtenay, Bryce
Penguin Books, 1999
Buku Teks
Morrison, Tony, author
Random House, 1995
Buku Referensi
Lembaga Penelitian Universitas Indonesia, 2007
Artikel Jurnal
Betts, R.J.
McGraw-Hill , 1980
Buku Teks