Vercelloni, Matteo, author
Edizioni L'archivolto, 1996
Buku Referensi
editors, James H. Carter, John Fellas
Oxford University Press, 2013
Buku Teks
Griffin, John I., author
City College Press, 1956
Buku Teks
edited by John W. Wrigth
Penguin Group, 2003
Buku Referensi
Cox, Joseph A.
Geboren Te, 1952
Buku Teks