Double relics in Abell 2345 and Abell 1240 - Spectral index and polarization analysis A. Bonafede, G. Giovannini, L. Feretti, F. Govoni and M. Murgia A&A, 494 2 (2009) 429-442 Published online: 20 November 2008 DOI: 10.1051/0004-6361:200810588