Nonlinear spring model for frictional stick-slip motion G. Djuidjé Kenmoé, A. Kenfack Jiotsa and T. C. Kofané Eur. Phys. J. B, 70 3 (2009) 353-361 Published online: 03 July 2009 DOI: 10.1140/epjb/e2009-00226-0