Salvemini, Gaetano
W.W. Norton & Company, 1962
Buku Teks
Thompson, J.M., author
Basil Blackwell, 1955.
Buku Teks
Carlyle, Thomas, author
E.P. Dutton, 1955
Buku Teks
Gershoy, Leo, author
Appleton Century Crofts, 1938
Buku Teks
Doyle, William, author
Oxford University Press , 1989
Buku Teks