Handsfield, H. Hunter, author
McGraw-Hill, 2011
Buku Teks
Wang, Gungwu, author
Panglaykim Fundation, 1997
Buku Teks
Tubilewicz, Czeslaw
New York : Routledge , 2007
Buku Teks
Long, David E.
Westview Press, 1985
Buku Teks
Martinus Nijhoff, 1963
Buku Referensi