X-ray spectral variability of the BL Lac object PKS2155-304: EXOSAT observations in 1985 Morini, M. ; Chiappetti, L. ; Maraschi, L. ; Molteni, D. ; Tanzi, E. G. ; Treves, A. Abstract Publication: Cosmic-Physics National Conference Pub Date: 1987 Bibcode: 1987cpnc.conf..169M