Keith, Arthur Berriedale, 1879-1944, author
Watts & Co., 1947
Buku Teks
Keith, Arthur, Sir, author
Watts & Co., 1950
Buku Teks
Ruse, Michael, author
Cambridge University Press, 2012
Buku Teks
Richardson, W. Norman, author
Macmillan, 1976
Buku Teks
Eckhardt, Robert B., author
McGraw-Hill, 1979
Buku Teks