edited by Astrik L. Gabriel
Mediaeval Institute, University of Notre Dame, 1974
Buku Teks
Mountford, James, Sir, author
Oxford Unniversity Press, 1966
Buku Teks
Kogan Page , 1986
Buku Teks
The World bank, 2007
Buku Teks
Mordechai Feingold, editor
Oxford University Press, 2016
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