Open access
Submitted: 23 October 2011 Published: 25 July 2012
DOI: 10.5772/39139
From the Edited Volume
Edited by Ginalber Luiz de Oliveira Serra
Submitted: 23 October 2011 Published: 25 July 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.