Non linear transport properties of an insulating YBCO nano-bridge L. Fruchter, A. Yu Kasumov, J. Briatico, A. A. Ivanov and V. Nicholaichik Eur. Phys. J. B, 73 3 (2010) 361-365 Published online: 15 January 2010 DOI: 10.1140/epjb/e2010-00014-9