Modulating coherence resonance in non-excitable systems by time-delayed feedback Paul M. Geffert, Anna Zakharova, Andrea Vüllings, Wolfram Just and Eckehard Schöll Eur. Phys. J. B, 87 12 (2014) 291 Published online: 03 December 2014 DOI: 10.1140/epjb/e2014-50541-2