Observations of Vela X-1 (3U0900-40) From OSO-8 Rothschild, R. ; Boldt, E. ; Holt, S. ; Serlemitsos, P. ; Becker, R. ; Swank, J. ; Pravdo, S. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: June 1976 Bibcode: 1976BAAS....8R.440R