Simultaneous multiwavelength observations of the second exceptional γ-ray flare of PKS2155–304 in July 2006 - Aharonian, Felix A.; Behera, Bagmeet; Emmanoulopoulos, Dimitrios; Hauser, Marcus; Kaufmann, Sarah; Pedaletti, Giovanna; Pühlhofer, Gerd; Quirrenbach, Andreas; Schwemmer, Stephanie; Wagner, Stefan (Astronomy and astrophysics, 2009)