Heilbroner, Robert L., author
Norton, 1974
Buku Teks
Ople, Blas F., author
The Institute for Public Policy, 2001
Buku Teks
Krutch, Joseph Wood, author
Greenwood Press, 1979
Buku Teks
Moran, Joe, author
Routledge, 2005
Buku Teks
Cambridge University Press, 2004
Buku Teks