Moving breather collisions in Klein-Gordon chains of oscillators A. Alvarez, F. R. Romero, J. Cuevas and J. F.R. Archilla Eur. Phys. J. B, 70 4 (2009) 543-555 Published online: 21 July 2009 DOI: 10.1140/epjb/e2009-00256-6