Communication in the twenty-first century
edited by George Gerbner, Richard B. Byrne
John Wiley & Sons, 1981
 Buku Teks
Public administration for the twenty-first century
by Phillip J. Cooper [and others]
Harcourt, Brace, 1998
 Buku Teks
Public administration for the Twenty-First century
by Phillip J. Cooper [and others]
Harcourt Brace, 1998
 Buku Teks
Capitalisms and capitalism in twenty-first century
edited by Glenn Morgan, Richard Whitley
Oxford University Press, 2012
 Buku Teks
Baker, Stanley B.
School counselling for the twenty-first century
Prentince-Hall, 1996
 Buku Teks