Black hole mass estimates in quasars - A comparative analysis of high- and low-ionization lines P. Marziani, A. del Olmo, M. A. Martínez-Carballo, M. L. Martínez-Aldama, G. M. Stirpe, C. A. Negrete, D. Dultzin, M. D’Onofrio, E. Bon and N. Bon A&A, 627 (2019) A88 Published online: 05 July 2019 DOI: 10.1051/0004-6361/201935265