Flux upper limits for 47 AGN observed with H.E.S.S. in 2004-2011 - Abramowski, Attila; Zacharias, Michael; Becherini, Yvonne; Cologna, Gabriele; Jankowsky, Felix; Kaufmann, Sarah; Mohamed, Mahmoud; Quirrenbach, Andreas; Schwemmer, Stephanie; Wagner, Stefan (Astronomy and astrophysics, 2014)