Schapiro, J. Salwyn
The world in crisis : political and social movement in the twentieth century
McGraw-Hill, 1950
 Buku Teks
Achmad Jainuri
The muhammadiyah movement in twentieth-century Indonesia : a socio-religius study
McGill University Montreal, 1992
 Buku Teks
Woodham, Jonatham M.
Twentieth-Century design
Oxford University Press, 1997
 Buku Teks SO
Chant, Christopher
Twentieth century war machines
London: Chancellor Press, 1999,
 Buku Referensi
Revolutions of the late twentieth century
edited by Jack A. Goldstone, Ted Robert Gurr, Farrokh Moshiri
Westview Press, 1991
 Buku Teks SO