Scaling and universality in models of step bunching: the “C+–C-” model V. Tonchev, B. Ranguelov, H. Omi and A. Pimpinelli Eur. Phys. J. B, 73 4 (2010) 539-546 Published online: 02 February 2010 DOI: 10.1140/epjb/e2010-00036-3