edited by Andrew Ballantyne
Routledge, 2002
Buku Teks
Hartley, John
Blackwell, 2008
eBooks
Carr, Edward Hallet
Vintage Books, 1961
Buku Teks
Norris, Christopher
Academy Editions, 1988
Buku Teks
Huber, Carlo
The Council for Research Values and Philosophy , 2001
Buku Teks