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Published online by Cambridge University Press: 30 March 2016
Recent progress in identifying the optical counterparts of X-ray sources has been slow, mostly because candidates are faint and X-ray data show no periodicities by which the identification can be confirmed. This report therefore deals with the investigation of some candidates to seek confirmation of their identity with the X-ray emitters, as well as details which are new or important concerning the few known binary sources. I shall also make some general remarks on the properties of the sources as they now appear, but leave a critical assessment of the masses to the next speaker.