Callaban, John F., author
Harvard University Press, 1948
Buku Teks
edited by Julia Annas
Clarendon Press , 1985
Buku Teks
Blackson, Thomas A., author
Wiley-Blackwell, 2011
Buku Teks
Mayer, Frederick, author
American Book Company, 1950
Buku Teks
edited by Julia Annas
Clarendon Press, 1984
Buku Teks