Open access
Submitted: 27 October 2010 Published: 21 October 2011
DOI: 10.5772/18486
From the Edited Volume
Edited by Margarita Stoytcheva
Submitted: 27 October 2010 Published: 21 October 2011
© 2011 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.