Erlbaum, 1996
Buku Teks
Tade Matthias Spranger
Springer, 2012
eBooks
Pollit, Christopher, author
Oxford University press, 2000
Buku Teks
Mark Bovens, Paul't Hart, B. Guy Peters
Edward Elgar Publishing, Inc, 2001
Buku Teks
Anna Galluzzi
Chandos , 2014
eBooks