Statt, David A.
Routledge, 1999
Buku Referensi
Friedman, Jack P.
Barron's Educational Series, 2007
Buku Referensi
Kurian, George Thomas
Amacom, 2013
Buku Referensi
Rosenberg, Jerry M.
John Wiley & Sons, 1993
Buku Referensi
Presner, Lewis A.
John Wiley & Sons, 1991
Buku Referensi