Henderson, W. O., author
University of California Press, 1975
Buku Teks
Nelson, Ralph L.
Russell Sage Foundation , 1967
Buku Teks
Strong, Anna Louise, author
New World Press, 1959.
Buku Teks
Pistrak, Lazar
Frederick A. Praeger, 1961
Buku Teks
Kandil, Hazem, author
Oxford University Press, 2016
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