Open access
Submitted: 18 November 2011 Published: 30 January 2013
DOI: 10.5772/50358
From the Edited Volume
Edited by Marcelino Kongo
Submitted: 18 November 2011 Published: 30 January 2013
© 2013 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.