F. Christensen, and B. Ramsey. (2022)cite arxiv:2207.00512Comment: 45 pages, 21 figures. Invited chapter for the 'Handbook of X-ray and Gamma-ray Astrophysics (Eds C.Bambini and A Santangelo, Springer Singapore, expected publication in 2022).
T. Siegert, D. Horan, and G. Kanbach. (2022)cite arxiv:2207.02248Comment: 75 pages, 25 figures, 1 table, accepted for the Handbook of X-ray and Gamma-ray Astrophysics.