The properties of the X-ray corona in the distant (z = 3.91) quasar APM 08279+5255 E. Bertola, C. Vignali, G. Lanzuisi, M. Dadina, M. Cappi, R. Gilli, G. A. Matzeu, G. Chartas, E. Piconcelli and A. Comastri A&A, 662 (2022) A98 Published online: 24 June 2022 DOI: 10.1051/0004-6361/202142642