Brecht, Arnold
Political theory: the foundations of twentieth-century political thought
Princenton University Press, 1968
 Buku Teks
Braun, Hans-Joachim
The German economy in the twentieth century / Hans-Joachim Braun
Routledge, 1990
 Buku Teks
Australian conservatism : essays in twentieth century political history
editor, Cameron Hazlehurst
Australian National University Press, 1979
 Buku Teks
The Routledge dictionary of twentieth-century political thinkers
edited by Robert Benewick and Philip Green
Routledge , 1992
 Buku Teks SO
The Economist : dictionary of political biography
Economist Books, 1991
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