Friedman, Thomas L.
Penguin Book, 2006
Buku Teks
Bruyn, Severyn T.
The University of Michigan Press, 2000
Buku Teks
Leming, Michael R.
Cengage Learning, 2016
Buku Teks
Hill, Napoleon
Ramala Books, 2007
Buku Teks
edited by Therese A. Rando
Research Press, 1986
Buku Teks