The ROSAT all-sky survey catalogue of optically bright OB-type starsT. W. Berghöfer, J. H.M.M. Schmitt and J. P. CassinelliAstron. Astrophys. Suppl. Ser., 118 3 (1996) 481-494DOI: https://doi.org/10.1051/aas:1996213