Threshold field in nucleation process for an inhomogeneous deformable nonlinear Klein-Gordon system R. L. Woulaché, D. Yemélé and T. C. Kofané Eur. Phys. J. B, 65 1 (2008) 99-108 Published online: 08 September 2008 DOI: 10.1140/epjb/e2008-00339-x