Chemical abundances along the quasar main sequence A. Floris, P. Marziani, S. Panda, M. Sniegowska, M. D’Onofrio, A. Deconto-Machado, A. del Olmo and B. Czerny A&A, 689 (2024) A321 Published online: 23 September 2024 DOI: 10.1051/0004-6361/202450458