Observation of the Extended X-Ray Source in the Crab Nebula by the SMC Experiment on HEAO-1 Briel, U. G. ; Bradt, H. ; Doxsey, R. ; Gursky, H. ; Oda, M. ; Ramsey, A. ; Schwarz, J. ; Schwartz, D. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: September 1977 Bibcode: 1977BAAS....9..627B