Sublattice ordering in a dilute ensemble of monovalent adatoms on graphene V. V. Cheianov, O. Syljuåsen, B. L. Altshuler and V. I. Fal'ko EPL, 89 5 (2010) 56003 Published online: 26 March 2010 DOI: 10.1209/0295-5075/89/56003