Janssen, Rainer, editor
Springer, 2012
eBooks
Marcus, Edward, author
Bookman Associates, 1960
Buku Teks
edited by Michael M. Horowitz and Thomas M. Painter
Westview Press, 1986
Buku Teks
Ezekiel Kalipeni, Juliet Iwelunmor, Diana Grigsby-Toussaint, Imelda Moise, editors
Routledge, Taylor & Francis Group, 2018
Buku Teks
edited by A.T. Dalfovo
The Council for Research in Values and Philosophy , 2002
Buku Teks