Double relics in Abell 2345 and Abell 1240 - Spectral index and polarization analysisA. Bonafede, G. Giovannini, L. Feretti, F. Govoni and M. MurgiaA&A, 494 2 (2009) 429-442DOI: https://doi.org/10.1051/0004-6361:200810588