Aubrey, Henry G., author
Frederick A. Praeger, 1964
Buku Teks
Plischke, Elmer
American Enterprise Institute for Public Policy Research, 1977
Buku Teks
SR Indonesia,
Majalah, Jurnal, Buletin
edited by Gordon Greenwood and Norman Harper
F.W. Cheshire, 1957
Buku Teks
Lovering, T.S.
Prentice-Hall, 1943
Buku Teks