Precise Positions of LMC X-1, X-2, and X-3 with the HEAO-1 Modulation Collimator Johnston, M. ; Bradt, H. ; Doxsey, R. ; Gursky, H. ; Schwartz, D. A. ; Schwarz, J. Abstract Publication: Bulletin of the American Astronomical Society Pub Date: March 1978 Bibcode: 1978BAAS...10..390J