Mates, Benson, author
Oxford University Press, 1965
Buku Teks
Copi, Irving M., author
Macmillan, 1972
Buku Teks
Huppe, Bernard Felix
Harpur, 1956
Buku Teks
Gibbins, Peter, author
Clarendon Press, 1988
Buku Teks
Lalement, Rene, author
Prentice-Hall, 1993
Buku Teks