Grawoig, Dennis E.
Petrocelli Books, 1982.
Buku Teks
Hubbard, L. Ron, 1911-1986, author
Bridge Publications, Inc., 2012
Buku Referensi
Bierman, Harold, author
The Free Press, 1980
Buku Teks
Machiavelli, Niccolo, author
American Heritage Press, 1969.
Buku Teks
Bullis, L. Harold
Westview Press, 1985
Buku Teks