Hoag, Erleen J.
Prentice-Hall, 1991
Buku Teks
edited by K. William Kapp, Lore L. Kapp
Barnes & Noble, 1949
Buku Teks
Kohler, Heinz
Alfred A. Knoff , 1961
Buku Teks
Commons, John R.
Macmillan, 1934
Buku Teks
Samuelson, Paul A. (Paul Anthony), 1915-2009
McGraw-Hill, 1985
Buku Teks