Sligo, John
Penguin Books, 1990
Buku Teks
Bailey, Thomas Andrew, 1902-1983, author
Cornell University Press, 1950
Buku Teks
Hetherington, John Aikman, 1907-, author
F.W. Cheshire, 1962
Buku Teks
Franve, Boyd
Washington, D.C. |Natiional Planning Ass. 1961,
Buku Teks
Shore, Cecilia M., author
Pearson, 2004
Buku Teks