Whitehead, Alfred North, 1861-1947, author
The Free Press , 1968
Buku Teks
Beattie, John, author
Free Press of Glencoe, 1966
Buku Teks
Beattie, John, author
The Free Press, 1964
Buku Teks
Mill, J.S.
Penguin Books, 1987
Buku Teks
Santayana, George, author
Columbia University Press, 1995
Buku Teks