Radio-optically selected clusters of galaxies - II. The cluster sample A. Zanichelli, R. Scaramella, G. Vettolani, M. Vigotti, S. Bardelli and G. Zamorani A&A, 379 1 (2001) 35-45 Published online: 15 November 2001 DOI: 10.1051/0004-6361:20011237