Abel, W. (1980). Agricultural fluctuations in Europe from the thirteenth to the twentieth centuries. St. Martin's Press.
Chicago-referens (17:e uppl.)Abel, Wilhelm. Agricultural Fluctuations in Europe from the Thirteenth to the Twentieth Centuries. New York: St. Martin's Press, 1980.
MLA-referens (9:e uppl.)Abel, Wilhelm. Agricultural Fluctuations in Europe from the Thirteenth to the Twentieth Centuries. St. Martin's Press, 1980.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.