Evans, G. R. (Gillian Rosemary), author
Open University Press, 2002
Buku Teks
Sahin, Muhammed, author
Emerald, 2016
eBooks
Feingold, Mordechai, author
Oxford University Press, 2017
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Artikel Jurnal
Carl Duisberg-Gesellsechft
Bonn Ferd, Dummlers Verlag
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