Rachels, James, 1941-2003
McGraw-Hill , 2012
Buku Teks
Weiss, Joseph
Wadsworth, 2009
Buku Teks
Hutcheson, Francis
Cambridge University Press, 2014
eBooks
Bendix, Reinhard
John Wiley & Sons, 1956
Buku Teks
Bendix, Reinhard
University of California Press, 1974
Buku Teks