The third-order perturbed Korteweg-de Vries equation for shallow water waves with a non-flat bottom M. Fokou, T. C. Kofané, A. Mohamadou and E. Yomba Eur. Phys. J. Plus, 132 10 (2017) 410 Published online: 03 October 2017 DOI: 10.1140/epjp/i2017-11709-0