Cooke, John
Pitman, 1992
Buku Teks
Winfield, P.H.
Sweet & Maxwell, Limited, 1948
Buku Teks
Kaplan, Morton A.
John Wiley & Sons, 1961
Buku Teks
Craswell, Richard
Oxford University Press, 1994
Buku Teks
Schuck, Peter H.
Oxford University Press, 1994
Buku Teks