Symmetry of standing waves generated by a point defect in epitaxial grapheneL. Simon, C. Bena, F. Vonau, D. Aubel, H. Nasrallah, M. Habar and J. C. PeruchettiEur. Phys. J. B, 69 3 (2009) 351-355DOI: https://doi.org/10.1140/epjb/e2009-00142-3