The Damping Tail of CMB Anisotropies by Wayne Hu and Martin White (1997)

Primary text: arxiv.org/pdf/astro-ph/9609079

Author paper page: background.uchicago.edu/~whu/damp/damppage.html

Cited passages: Sections 2.1–2.2, photon Boltzmann equations and diffusion/reionization damping mechanisms. ArXiv submission1996; Astrophysical Journal479,568–579(1997). Authors verified on title page.