Bill, James A., author
Littel Brown and Company, 1984
Buku Teks
edited by Robert O. Freedman
Westview Press, 1984
Buku Teks
Harari, Maurice, author
Prentice-Hall, 1962
Buku Teks
Palmer, Monte, author
Thomson Wadsworth, 2007
Buku Teks
Andersen, Roy R., author
Pearson/Prentice Hall, 2007
Buku Teks