Lesley
Grange Books, 1996
Buku Teks
Adkins, Lesley
Cambridge University Press, 1989
Buku Teks
Staeck, John P., author
Mayfield Publishing Company, 2002
Buku Teks
Paor, Liam de
Penguin Books , 1967
Buku Teks
edited by Mari Pritchard Parker, Elvio Angeloni
McGraw-Hill, 2013
Buku Teks