edited by Martin E. Liggins, David L. Hall, James Llinas
CRC Press, 2009
Buku Referensi
Searles, William H.
John Wiley & Sons, 1949
Buku Referensi
Armstrong, Michael
Kogan Page Limited, 1995
Buku Referensi
edited by John S. Dryzek, Bonnie Honig, Anne Phillips
Oxford University Press, 2008
Buku Referensi
edited by Jeffrey J. Magnavita
John Wiley & Sons, 2003
Buku Teks