The HEAO A-2 Survey of Abell Clusters and the X-Ray Luminosity Function McKee, J. D. ; Mushotzky, R. F. ; Boldt, E. A. ; Holt, S. S. ; Marshall, F. E. ; Pravdo, S. H. ; Serlemitsos, P. J. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: March 1980 Bibcode: 1980BAAS...12..486M