2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12494We 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.3 pages, 1 figure, to appear in: Proc. of the 26th workshop of the European Working Group on CP stars, eds. P. North, A. Schnell and J. Ziznovsky, Contrib. Astr. Obs. Skalnate Pleso Vol. 27, No 3Astrophysicstext