Wellburn, Alan
Addison-Wesley, 1996
Buku Teks
edited by Richard W. Battarbee, Heather A. Binney
Wiley-Blackwell, 2008
Buku Teks
Quinto, Cornel
Springer, 2012
eBooks
Friedman, Thomas L.
Farrar, Straus and Giroux, 2008
Buku Teks
Numberi, Freddy
Fortuna, 2009
Buku Teks