Holdsworth, William, Sir, author
Methuen, 1938
Buku Teks
Hanbury, Harold Grenville, author
Methuen, 1956
Buku Teks
Doe, Norman, author
Cambridge University Press, 1990
Buku Teks
Schwartz, Bernard, author
McGraw-Hill, 1974
Buku Teks
Hall, Kermit L.
Oxford University Press, 1989
Buku Teks