Pinning of cracks in two-dimensional disordered media J. Rosti, L. I. Salminen, E. T. Seppälä, M. J. Alava and K. J. Niskanen Eur. Phys. J. B, 19 2 (2001) 259-263 Published online: 15 January 2001 DOI: 10.1007/s100510170334