Cohen, John Michael, 1903-1989
The Penguin dictionary of twentieth-century quotations
Viking, 1993
 Buku Referensi
Teed, Peter
A dictionary of twentieth century history 1914-1990
Oxford University Press , 1992
 Buku Referensi
Black, C.E.
Twentieth Century Europa: a history
Alfred A. Knopf, 1961
 Buku Teks
Black, C.E.
Twentieth Century Europe: a history
Alfred A. Knopf, 1966
 Buku Teks
Biographical dictionary of twentieth-century philosophers
edited by Stuart Brown, Diane Collinson, Robert Wilkinson
Roudledge, 1996
 Buku Referensi