Grenville, J.A.S.
A history of the world : from the 20th to the 21st century
Routledge, 2005
 Buku Teks SO
Kotter, John P., 1947-
Matsushita Leadership : lessons from the 20th century's most remarkable entrepreneur
Free Press, 1997
 Buku Teks
Fergany, Nader
Arab revolution in the 21st century?: lessons from Egypt and Tunisia
Palgrave Macmillan, 2016
 Buku Teks SO
Eky Triwulan Kusumaningrum
Pemenuhan hasrat: sebuah kajian psikoanalitik komik 20th Century Boys dan 21st Century Boys karangan Naoki Urasawa
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2011
 UI - Skripsi Open
Chambers 20th century dictionary
edited by E.M. Kirkpatrick ; assistant editors, C.M. Schwarz ... [and others]
Chambers, 1983
 Buku Referensi