edited by Robert E. Goodin, Charles Tilly
Oxford University Press, 2008
Buku Referensi
Sommer, Robert
Oxford University Press, 2001
Buku Teks
Davis, Leonard G.
Appleton & Lange, 1994
Buku Teks
Tu, Anthony T., 1930-
John Wiley & Sons, 1982
Buku Teks
Woodger, J.H.
Cambridge University Press, 1952
Buku Teks