Audi, Robert, author
Routledge, 2011
Buku Teks
Rescher, Nicholas, author
State University of New York Press, 2003
Buku Teks
Edited by Michael Huemer
Routledge, 2002
Buku Teks
edited by Ben Kotzee
Wiley-Blackwell, 2014
Buku Teks
O`Brien, Dan, author
Polity Press, 2006
Buku Teks