Frascona, Joseph L.
Prentice Hall, INC, 1964
Buku Teks
Justice M. Taqui Usmani, author
Rightway Publication, 2002
Buku Teks
Barreto, Luis Filipe
Imprensa Nacional, 1988
Buku Referensi
Zichy, Shoya, author
American Management Association, 2007
eBooks
Dorsett, Joseph L.
Allyin and Bacon, 1972
Buku Teks