Open access
Submitted: 28 October 2010 Published: 20 January 2012
DOI: 10.5772/18587
From the Edited Volume
Edited by Artur de Jesus Motheo
Submitted: 28 October 2010 Published: 20 January 2012
© 2012 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.