Singer, J. David
Westview Press , 1990
Buku Teks
Centre William Rappard , 1999
Buku Teks
Perkins, Dexter
Indiana University Press, 1963
Buku Teks
Kyung Hee Univerity Press, [date of publication not identified]
Buku Teks
T. David Marson; James D. Meernik, editor
Routledge, 2006
Buku Teks