  Was star formation in the OB associations, LH 51 and LH 54, triggered by the
growth of the superbubble DEM 192? To examine this possibility, we investigate
the stellar contents and star formation history, and model the evolution of the
shell. H-R diagrams constructed from UBV photometry and spectral
classifications indicate highly coeval star formation, with the entire massive
star population having an age of ~< 2-3 Myr. However, LH 54 is constrained to
an age of ~3 Myr by the presence of a WR star, and the IMF for LH 51 suggests a
lower-mass limit implying an age of 1-2 Myr. There is no evidence of an earlier
stellar population to create the superbubble, but the modeled shell kinematics
are consistent with an origin due to the strongest stellar winds of LH 54. It
might therefore be possible that LH 54 created the superbubble, which in turn
may have triggered the creation of LH 51. Within the errors, the spatial
distribution of stellar masses and IMF appear uniform within the associations.
  We reinvestigate the estimates for stellar wind power L_w(t), during the
H-burning phase, and note that revised mass-loss rates yield a significantly
different form for L_w(t), and may affect stellar evolution timescales. We also
model superbubble expansion into an ambient medium with a sudden, discontinuous
drop in density, and find that this can easily reproduce the anomalously high
shell expansion velocities seen in many superbubbles.
