Forsythe, David P., 1941-, author
University of Nebraska Press, 1983
Buku Teks
Erika De Wet and Jure Vidmar, editors
Oxford university press, 2012
Buku Teks
edited by Dinah Shelton
Oxford University Press, 2013
Buku Teks
Unesco, 1970
Buku Teks
Constantinou, Costas M., author
Sage Publications, 2016
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