Brophy, Peter
The library in the twenty-first century : new services for the information age
Library Association Publishing, 2002
 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
Public administration for the twenty-first century
by Phillip J. Cooper [and others]
Harcourt, Brace, 1998
 Buku Teks