Her X-1 Hard X-Ray Pulsations Observed from HEAO-1 Gruber, D. E. ; Matteson, J. L. ; Nolan, P. ; Knight, F. K. ; Hoffman, J. A. ; Scheepmaker, A. ; Lewin, W. H. G. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: December 1979 Bibcode: 1979BAAS...11..701G