Jackson-Moore, Elisabeth
Global Professional, 2009
Buku Teks SO
Edinburgh University Press, 2004
Buku Teks SO
Lahsasna, Ahcene
Wiley, 2014
Buku Teks SO
Greuning, Hennie van
World Bank, 2008
Buku Teks SO
El-Gamal, Mahmoud A
Cambrigde University Press , 2009
Buku Teks