@Article{ dallaz09, author = { Gianni Dal Maso and Giuliano Lazzaroni }, title = { Crack growth with non-interpenetration: a simplified proof for the pure Neumann problem }, journal = { Discrete Contin. Dyn. Syst. (DCDS-A) }, year = { 2011 }, volume = { 31 }, number = { 4 }, pages = { 1219-1231 }, }