Williamson, Oliver E., author
Markham, 1967
Buku Teks
Boyes, William, author
South Western Cengage Learning, 2012
Buku Teks
Thompson, Arthur A., 1940-, author
Prentice-Hall, 1989
Buku Teks
Maurice
Buku Teks
Farrar, Donald E., author
Prentice-Hall, 1970
Buku Teks