@Article{ bracic03, author = { Braides, Andrea and Cicalese, Marco }, title = { Surface energies in nonconvex discrete systems }, journal = { Math. Mod. Meth. Appl. Sci. (M3AS) }, year = { 2007 }, volume = { 17 }, pages = { 985-1037 }, URL = { http://cvgmt.sns.it/paper/1225/ }, note = { cvgmt preprint} }