J. David Reitzel [and others]
McGraw-Hill, 1990
Buku Referensi
Fitzmaurice, Malgosia, author
Edward Elgar, 2009
Buku Teks
by Ralph C. Hoeber ... [et al.]
McGraw-Hill, 1986
Buku Teks
Morkuniene, Jurate
Council for Research in Values and Philosophy, 2004
Buku Teks
James P Sterba
Routledge, 2001
Buku Teks