Friedman, Thomas L.
The world is flat : the globalized world in the twenty-first century
Penguin Book, 2006
 Buku Teks SO
Al-Suwaidi, Jamal Sanad
United Arab Emirates society in the twenty-first century: issues and challenges in a changing world
Jamal Sanad Al-Suwaidi, 2018
 Buku Teks SO
Statistics for the twenty-first century
edited by Florence S. Gordon and Sheldon Gordon
Mathematical Association of America, 1992
 Buku Teks SO
Communication in the twenty-first century
edited by George Gerbner, Richard B. Byrne
John Wiley & Sons, 1981
 Buku Teks
Russel, Fox Hon
Justice in the twenty-first century
Covendish Publishing Limited, 2000
 Buku Teks