Erratum to: “Development of a Super-Stable Datum Point for Monitoring the Energy Scale of Electron Spectrometers in the Energy Range up to 20 keV” by D. Vénos, M. Zbořil, J. Kašpar, O. Dragoun, J. Bonn, A. Kovalík, O. Lebeda, N. A. Lebedev, M. Ryšavý, K. Schlösser, A. Špalek, and Ch. Weinheimer, Vol. 53, No. 3, pp. 305–312, July, 2010