A critical analysis of the UV luminosity function at redshift ~7 from deep WFC3 data A. Grazian, M. Castellano, A. M. Koekemoer, A. Fontana, L. Pentericci, V. Testa, K. Boutsia, E. Giallongo, M. Giavalisco and P. Santini A&A, 532 (2011) A33 Published online: 18 July 2011 DOI: 10.1051/0004-6361/201015754