edited by David Kelleher and Sheila Hillier
Routledge, 1996
Buku Teks
Kamerman, Sheila B.
Temple University Press, 1976
Buku Teks
Brokings Institution, 1950
Buku Teks
Brookings institution, 1949
Buku Teks
Anderson, Odin W.
John Wiley & Sons, 1972
Buku Teks