Manimala, Varghese
Council for Research in Values and Philosophy , 2008
Buku Teks
Cooper, Karyn
Springer, 2012
eBooks
Burton, Steven J.
Canbridge University Press, 1992
Buku Teks
edited by Charles Jencks
Academy Editions, 1992
Buku Teks
The Free Press of Glencoe, 1961
Buku Teks