Realization of a quantum standard for AC voltage: overview of a European research project. - Oleg A. Chevtchenko; Helko E. van den Brom; Ernest Houtzager; Ralf Behr; Johannes Kohlmann; Jonathan M. Williams; Theodoor J. B. M. Janssen; Luis Palafox; David A. Humphreys; François P. M. Piquemal; Sophie Djordjevic; O. Monnoye; et al. (IEEE Trans. Instrum. Meas., 2005)