X-Ray Mapping with HEAO-1 Szymkowiak, A. E. ; Shafer, R. A. ; Boldt, E. A. ; Holt, S. S. ; Serlemitsos, P. J. ; Rothschild, R. E. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: March 1978 Bibcode: 1978BAAS...10Q.421S