edited by E.L. Baum, Howard G. Diesslin and Earl O. Heady
Iowa State University Press, 1961
Buku Teks
Wilson, Bryan
I.B. Tauris , 2008
Buku Teks
Irwin, Terry
Churchill Livingstone, 2004
Multimedia
Thurow, Lester C., editor
Wadsworth, 1970
Buku Teks
edited by Kristian Bolin, Bojrn Lindgren, Michael Grossman, Dorte Gyrd-Hansen, Tor Iversen, Robert Kaestner, Jody L. Sindelar
Emerald, 2017
eBooks