Dye, Thomas R., author
Thomson, 2006
Buku Teks
Dye, Thomas R., author
Harcourt Brace College, 2000
Buku Teks
Sage Publications, 2012
eBooks
Padover, Saul K. (Saul Kussiel), author
Frederick A. Praeger, 1963
Buku Teks
Mayo, Henry B., author
Oxford University Press , 1960
Buku Teks