McMurry, John, author
Brooks/Cole, 2007
Buku Teks
Bruice, Paula Yurkanis, author
Upper Saddle River, 2001
Buku Teks
Neckers, Douglas C.
John Wiley & Sons, 1977
Buku Teks
Morrison, Robert Thornton, author
Prentice-Hall, 1992
Buku Teks
Lehman, John W., author
Upper Saddle River, 2008
Buku Teks