Genzmer, Herbert, author
Parragon, 2010
Buku Referensi
Gropin, Marc
Oxford University Press, 2002
Buku Teks
Armstrong, Karen, author
Doubleday, 1991
Buku Teks
Machen, Arthur, author
Penguins Books, 1946
Buku Teks
Ehrlich, J. W., author
Oceana Publications, 1962
Buku Teks