Henderson, I. F., author
Harlow, England Longman Scientific and Technical
Buku Referensi
Deutsch, Babette, author
Funk & Wagnalls, 1957
Buku Referensi
Downes, John, author
barron's, 2006
Buku Teks
Friedman, Jack P., author
Barron's Educational Series, 2007
Buku Referensi
Hildreth, Sandra S., author
Dearborn Financial Publishing, 1988
Buku Referensi