Kaldor, Nicholas
Allen & Uniwin , 1955
Buku Teks
edited by Douglas A. Kahn
Little, Brown, 1981
Buku Teks
McGovern, William M., author
St. Paul Minn, 1988
Buku Teks
edited by Emile Woolf
Pitman, 1986
Buku Teks
Stanford, David R.
London, Sweet & Maxwell Limited
Buku Teks