The abundance of clustered primordial black holes from quasar microlensing Sven Heydenreich, Evencio Mediavilla, Jorge Jiménez-Vicente, Héctor Vives-Arias and Jose A. Muñoz A&A, 690 (2024) A307 Published online: 17 October 2024 DOI: 10.1051/0004-6361/202449216