St. Martin's Press, 1990
Buku Teks
Stockwin, J. A. A.
Cambridge University Press , 1968
Buku Teks
University Press of America, 1978
Buku Teks
by Frank B. Feigert ... [et al.] ; edited by Don C. Piper and Ronald J. Terchek
American Enterprise Institute for Public Policy Research, 1983
Buku Teks
Aharoni, Yair, author
Harvard University, 1966
Buku Teks