Wilczynski, J.
Macmillan, 1976
Buku Teks
Salemba Empat, 2014
Buku Teks
edited by Lorraine Eden
St. Martin's Press, 1993
Buku Teks
Waldmann, Raymond J.
American Enterprise Institute , 1980
Buku Teks
Fitzgerald, Robert, 1959-, author
Cambridge University Press, 2015
Buku Teks