Legge, John D., author
Prentice-Hall, 1964
Buku Teks
Grant, Bruce, 1925-, author
Penguin Books, 1967
Buku Teks
Sritua Arief, author
Lembaga Studi Pembangunan, 1981
Buku Teks
Butwell, Richard, author
Ginn, 1967
Buku Teks
National Planning Association , 1957
Buku Teks