Eun-Ah Kim, Michael J Lawler, Smitha Vishveshwara, Eduardo FradkinPhys. Rev. B. 74, 155324. DOI: http://dx.doi.org/10.1103/PhysRevB.74.155324. arXiv:cond-mat/0604325 Friday, October 27, 2006 PhysRevB2006Kim-1.pdf