Jiang, Y.; Lee, S. B.; Herzog-Arbeitman, J.; Yu, J.; Feng, X.; Hu, H.; Cǎlugǎru, D.; Brodale, P. S.; Gormley, E. L.; G. Vergniory, M.et al.; Felser, C.; Blanco-Canosa, S.; Hendon, C. H.; Schoop, L. M.; Bernevig, B. A.: Pb9Cu(PO4)6(OH)2: Phonon bands, localized flat-band magnetism, models, and chemical analysis. Physical Review B 108 (23), 235127, pp. 1 - 14 (2023)