HEAO-1 Observations of High Energy X-Rays from 3C 273 Primini, F. A. ; Cooke, B. A. ; Dobson, C. A. ; Howe, S. K. ; Wheaton, W. A. ; Lewin, W. H. G. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: September 1978 Bibcode: 1978BAAS...10R.689P