Walker, Warren F.
Saunders College Pub., 1986
Buku Referensi
Press, Frank, author
W.H. Freeman and Company, 1986
Buku Referensi
Russell, Roberta S.
Prentice-Hall, 2000
Multimedia
Russell, Roberta S.
Prentice-Hall, 2000
Multimedia
Vaughan, Terry A.
Saunders College Publishing, 1986
Buku Referensi