Bonner, Thomas Neville
Prentice-Hall, 1963
Buku Teks SO
edited by Kader Asmal, Davud Chidester and Wilmot James
Abacus, 2013
Buku Teks SO
Gorman, Michael
[American Library association;American Library association, American Library association], 2005
eBooks
U.S. Goverment, 2003
Buku Teks SO
Hall, John Oliver
American Book Company, 1958
Buku Teks SO