Bryson, Bill
I'm a stranger here myself : notes on returning to America after twenty years away
Broadway Books, 2000
 Buku Teks
Drucker, Peter Ferdinand, 1909-2005
America's next twenty years
Harper & Brothers, 1957
 Buku Teks
Davidson, Jamie S.
Indonesia: twenty years of democracy
Cambridge University Press, 2018
 Buku Teks
Literature and psychoanalysis : the Question of reading: otherwise
edited by Shoshana Felman
Johns Hopkins University Press, 1985
 Buku Teks SO
Celebrating twenty years with Deloitte in Indonesia
Deloitte Touche Tohmatso limited
Deloitte Touche Tohmatso limited, 2010
 Buku Referensi