Oxford University Press, 2005
Buku Teks
Lawrence J Vale
Oxford University Press, 2005
Buku Teks
Tumlin, Jeffrey, author
John Wiley & Sons, 2012
Buku Teks
Brown, Lance Jay, author
Wiley, 2014
Buku Teks
Owen, Wilfred
The Brookings Institution, 1972
Buku Teks