Gorlewski, Julie A.
Sense, 2012
eBooks
Protherough, Robert
Open University Press, 1991
Buku Teks
Thomas, David A.
Allyn and Bacon, 1991
Buku Teks
The Library Unesco/Rostsea
Unesco/Rostsea, 1992
Buku Referensi
Lawrence, David Herbert, 1885-1930
Ballantine Books, 1969
Buku Teks