X-Ray Spectra of Clusters of Galaxies from OSO-8 Smith, B. W. ; Mushotzky, R. F. ; Serlemitsos, P. J. ; Boldt, E. A. ; Holt, S. S. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: September 1977 Bibcode: 1977BAAS....9R.559S