 A new approach to the evolution of cosmological perturbations on large scales by David Wands and others

Primary text: arxiv.org/pdf/astro-ph/0003278

Cited passages: Sections II–V, equations (5)–(8), (18)–(19), (29): gauge-invariant uniform-density curvature, nonadiabatic-pressure/gradient conditions and generalized adiabatic perturbations. Title page author list inspected: David Wands, Karim A. Malik, David H. Lyth, Andrew R. Liddle. Only the first-author name is used by the source header; no unverified personal metadata added.