Russell, Lou
Critical competencies for 21st century leaders
American Society for Training & Development, 2012
The conscious voice: an anthology of American poetry from the seventeenth century to the present
edited by Albert D. van Nostrand and Charles H. Watts
Library Arts Press, 1959
 Buku Teks
Developing leaders for positive organizing: a 21st century repertoire for leading in extraordinary times
lead editor, Rob Koonce
Emerald, 2017
Tatum Syarifah Adiningrum
It right : the importance of communication skills to 21st century educational leaders
[Publisher not identified], 2011
 Artikel Jurnal
Leaders Magazine,
 Majalah, Jurnal, Buletin