Errata for "Fluid Models for Landau Damping with Application to the Ion-Temperature-Gradient Instability", G.W. Hammett and F.W. Perkins, Phys. Rev. Lett. 64, 3019 (1990):

In the first line of Eq., 8, the factor of $e^{i k}$ should be $e^{i k z}$.