Holdsworth, William, Sir, author
Methuen, 1938
Buku Teks
Hanbury, Harold Grenville, author
Methuen, 1956
Buku Teks
Eyre & Spottiswoode, 1955
Buku Teks
Doe, Norman, author
Cambridge University Press, 1990
Buku Teks
Atkins, J.W.H., author
Methuen, 1951
Buku Teks