Weak long-ranged Casimir attraction in colloidal crystals A. Gopinathan, T. Zhou, S. N. Coppersmith, L. P. Kadanoff and D. G. Grier Europhys. Lett., 57 3 (2002) 451-457 Published online: 01 September 2002 DOI: 10.1209/epl/i2002-00481-1