Barry, Brian, author
Clarendon, 1973
Buku Teks
Newton, K.M.
Harvester Wheatsheaf , 1990
Buku Teks
Gerung, Rocky, author
Universitas Indonesia, 1991
UI - Skripsi (Membership)
Kyburg, Henry E., author
Prentice-Hall, 1969
Buku Teks
Gould, Ronald, author
The Benjamin Cumming , 1988
Buku Teks