Easton, David, author
John Wiley & Sons, 1965
Buku Teks
edited by Robert E. Goodin, Charles Tilly
Oxford University Press, 2008
Buku Referensi
Sargent, Lyman Tower, author
The Dorsey Press, 1981
Buku Teks
Sargent, Lyman Tower, author
Wadsworth , 2009
Buku Teks
Moten, Abdul Rashid, author
Thomson, 2006
Buku Teks