Trevelyan, George Macaulay, 1876-1962, author
Longmans, Green, 1945
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International Institute For Applied Systems Analysis, 1981
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Wilson, John Dover, compiler
University Press, 1926
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Belitz, H.D., author
Springer-Verlag, 1986
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Earle, Liz, author
Boxtree, 1995
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