AGN and QSOs in the eROSITA All-Sky Survey - I. Statistical properties Alexander Kolodzig, Marat Gilfanov, Rashid Sunyaev, Sergey Sazonov and Marcella Brusa A&A, 558 (2013) A89 Published online: 08 October 2013 DOI: 10.1051/0004-6361/201220880