edited by Stuart Friebert
Longman, 1989
Buku Teks
Gert J. J. Biesta
Springer, 2012
eBooks
Neumann, Victor, author
The Council for Research in Values and Philosophy , 2000
Buku Teks
edited and commented upon by Robert Ulich
Harvard University Press, 1947
Buku Teks
edited by E. Stuart Kirby
Oxford University Press, 1956
Buku Teks