Davies, W.H.
J. Cape,, 1927
Buku Teks
Davies, W. H.
Jonathan Cape, 1933
Buku Teks
Heydenreich, Ludwig
Yale University Press, 1996
Buku Teks
Anderson, Edward William
Baillière Tindall & Cassell, 1979
Buku Teks
Kautsky, John H., author
Krieger Pub. Co, 1980
Buku Teks