edited by Jaume Puig-Junoy
Edward Elgar, 2005
Buku Teks
Vernon, Raymond, author
Free Press, 1989
Buku Teks
Martin, Stephen, 1961-, author
Maxwell Macmillan International, 1994
Buku Teks
Perkins, Dexter
Harvard University Press, 1954
Buku Teks
by James W. Ceaser ... [and others]
McGraw-Hill , 1984
Buku Teks