Discovery of a redshift 6.13 quasar in the UKIRT infrared deep sky survey D. J. Mortlock, M. Patel, S. J. Warren, B. P. Venemans, R. G. McMahon, P. C. Hewett, C. Simpson, R. G. Sharp, B. Burningham, S. Dye et al. (3 more) A&A, 505 1 (2009) 97-104 Published online: 22 June 2009 DOI: 10.1051/0004-6361/200811161