Diffuse radio emission in the merging cluster MACS J0717.5+3745: the discovery of the most powerful radio haloR. J. van Weeren, H. J. A. Röttgering, M. Brüggen and A. CohenA&A, 505 3 (2009) 991-997DOI: https://doi.org/10.1051/0004-6361/200912528
