Corwin, Edward S., author
Princeton University press, 1958
Buku Teks
edited by Monrad G. Paulsen
Columbia University Press, 1959
Buku Teks
Bardes, Barbara A., author
Thomson/Wadsworth, 2006
Buku Teks
Kelly, Gery F., author
McGraw-Hill, Higher Education, 2008
Buku Teks
edited by Philip John Davies and Fredric A. Waldstein
Manchester University Press, 1987
Buku Teks