The Average X-ray/Gamma-ray Spectra of Seyfert Galaxies from Ginga and OSSE Zdziarski, A. A. ; Johnson, W. N. ; Done, C. ; Smith, D. ; McNaron-Brown, K. Abstract Publication: New Horizon of X-Ray Astronomy. First Results from ASCA Pub Date: January 1994 Bibcode: 1994nhxr.conf..601Z