Wolfe, Gerard R.
McGraw-Hill, 1994
Buku Referensi
Appleton, Julian J.
Practicing Law Institute, 1947
Buku Teks
Rosenfeld, Paul
University of Illinois, 1961
Buku Teks
Rutherfurd, Edward
Ballantine Books Trade Paperbacks, 2010
Buku Teks SO
Waugh, Evelyn, 1903-1966
Everyman's Library , 1998
Buku Teks SO