The incidence of nonradial pulsation in the lambda Bootis stars
  We have completed a high-resolution, high-signal-to-noise, spectroscopic survey of the northern members of the peculiar lambda Boo stars in order to investigate the frequency of the incidence of nonradial pulsation (NRP) in these metal-deficient stars. Of 18 objects observed, 9 show conclusive evidence of NRP, which suggests that pulsation instability is a common phenomenon in the lambda Boo class. 
D.A. Bohlender (1), J.-F. Gonzalez (2,3), J.M. Matthews (4) ((1)   Victoria, Canada, (2) ENS de Lyon, France, (3) ESO, Chile...