Interaction properties of the periodic and step-like solutions of the double-Sine-Gordon equation Marzieh Peyravi, Afshin Montakhab, Nematollah Riazi and Abdorrasoul Gharaati Eur. Phys. J. B, 72 2 (2009) 269-277 Published online: 10 October 2009 DOI: 10.1140/epjb/e2009-00331-0