Cambridge University Press, 1979
Buku Teks
Maasdorp, A.F.S., Sir
Juta & Co., 1948
Buku Teks
Departemen Luar Negeri, 2004
Buku Teks
edited by Jean-Jacques Hublin, Shannon P. McPherron
Springer Science, 2012
eBooks
edited by Virginia Gamba-Stonehouse
Institute for Security Studies, 2000
Buku Teks