Gordon, Scott
Columbia University Press, 1980
Buku Teks
Warburton, Nigel, 1962-, author
Routledge, 2001
Buku Teks
Departmen of Social Affairs United Nations
Departmen of Social Affairs United Nations, 1950
Buku Teks
Diamond, Louise
Kumarian Press, 1996
Buku Teks
edited by Herman Wasserman
Routledge, 2013
Buku Teks