Seidman, Ann W.
Centre Against Aparthed, Department of Political and Security Council Affairs, United Nations , 1978
Buku Teks
Nielsen, Waldemar A.
Atheneum, 1966
Buku Teks
Lipton, Merle
Witwatersrand University Press, 1993
Buku Teks
edited by C. Grove Haines
John Hopkins Press, 1956
Buku Teks
Schalkwyk, Herman D. van
[;Wageningen Academic, Wageningen Academic], 2012
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