Radial velocity of an epoch relative to the mean of the velocities of all epochs that the star was observed in km s^-1 with 1σ uncertainties. These relative velocities have also been listed in Table 1. The vertical dotted lines delineate from left to right, the B-supergiants, the YHG hypergiants (and the LBV W243), the M supergiants, and the sgB[e] star W9. Only the stars W56, W238 and W9 are consistent with having no radial velocity variations.