Alvin Y. So, author
Sage Publications, 1990
Buku Teks
Heath, Robert W.
Harper and Row, 1964
Buku Teks
Jones, Gareth R., author
Pearson, 2010
Buku Teks
Jones, Gareth R., author
Pearson Education. Inc, 2004
Buku Teks
Jones, Gareth R., author
Pearson Prentce-Hall, 2007
Buku Teks