Weeks, Daniel P.
Saunders College , 1998
Buku Teks
Morrison, Robert Thornton, author
Prentice-Hall, 1992
Buku Teks
Morrison, Robert Thornton, author
Allyn and Bacon, 1973
Buku Teks
Neckers, Douglas C.
John Wiley & Sons, 1977
Buku Teks
Fessenden, Ralph J., author
Willard Grant Press, 1979
Buku Teks