Friedman, Thomas L., author
Anchor Books, 2000
Buku Teks
Linton, Adelin, author
Columbia University Press, 1971
Buku Teks
Sierra, Kathy, author
O'Reilly, 2003
Buku Teks
Friedman, Thomas L, author
Picador, 2012
Buku Teks
Bickley, Lynn S., author
Lippincott Williams & Wilkins, 2007
Buku Teks