Amsterdam : Elsevier Science Publishers
Majalah, Jurnal, Buletin
Hogan, Patrick Colm, author
Routledge, 2005
Buku Teks
Tubingen : Federal Republic of Germany
Majalah, Jurnal, Buletin
edited, Suman Gupta, David Johnson
Routledge , 2005
Buku Teks
Pojman, Louis P., author
New York : Oxford University Press, 2000
Buku Teks