Catterberg, Edgardo
Lynne Rienner, 1990
Buku Teks
Deutsch, Karl W
Houghton Mifflin, 1970
Buku Teks
Thomson Wadsworth, 2003
Multimedia
edited by Roy C. Macridis, Bernard E. Brown
Dorsey Press, 1968
Buku Teks
Magstadt, Thomas M., author
Wadsworth-Cengage learning, 2009
Buku Teks