APA-referens (7:e uppl.)
Barraclough, G. (1976). The Crucible of Europe: The Ninth and Tenth Centuries in European History. University of California Press.
Chicago-referens (17:e uppl.)
Barraclough, Geoffrey. The Crucible of Europe: The Ninth and Tenth Centuries in European History. Berkeley: University of California Press, 1976.
MLA-referens (9:e uppl.)
Barraclough, Geoffrey. The Crucible of Europe: The Ninth and Tenth Centuries in European History. University of California Press, 1976.
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