Observation of a new non-equilibrium state in superconductors caused by sequential tunnellingA. G. Kozorezov, J. K. Wigmore, A. Peacock, R. den Hartog, D. Martin, G. Brammertz, P. Verhoeve and N. RandoEurophys. Lett., 66 2 (2004) 265-271DOI: https://doi.org/10.1209/epl/i2003-10181-4