Turner, Bryan S.
Sage, 1983
Buku Teks
Council for Research in Values and Philosophie, 2004
Buku Teks
Wasby, Stephen L.
Charles Scribner`s Sons, 1973
Buku Teks
Nancy LoPatin-Lummis, editor
Wiley-Blackwell, 2008
Buku Teks
The Free Press, 1971
Buku Teks