Zopf, Paul E,Jr
Mayfield Publishing, 1984
Buku Teks
Hammond, Peter, author
Macmillan, 1978
Buku Teks
Vaughan, Graham M., author
Pearson Prentice Hall, 2005
Buku Teks
Hicks, John R., author
Oxford University Press, 1975
Buku Teks
Orenstein, Alan
The Falmer Press, 1978
Buku Teks