A.  Herpers, Lenser, C., Park, C., Offi, F., Borgatti, F., Panaccione, G., Menzel, S., Waser, R., and Dittmann, R., ?Spectroscopic Proof of the Correlation between Redox-State and Charge-Carrier Transport at the Interface of Resistively Switching Ti/PCMO Devices?, Advanced materials (Weinh., Print), vol. 26, pp. 2730?2735, 2014.