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
Revolutions of the late twentieth century
edited by Jack A. Goldstone, Ted Robert Gurr, Farrokh Moshiri
Westview Press, 1991
 Buku Teks
Varga, Eugen, 1879-1964
Twentieth century capitalism
Foreign Languages Publishing House, 1961
 Buku Teks
Kohn, Hans
African nationalism in the twentieth century
D. Van Nostrand, 1965
 Buku Teks