Effect of N doping and Stone-Wales defects on the electronic properties of graphene nanoribbons H. Zeng, J. Zhao, J. W. Wei and H. F. Hu Eur. Phys. J. B, 79 3 (2011) 335-340 Published online: 14 January 2011 DOI: 10.1140/epjb/e2010-10725-4