GTC spectra of z ≈ 2.3 quasars: comparison with local luminosity analogsJack W. Sulentic, Paola Marziani, Ascensión del Olmo, Deborah Dultzin, Jaime Perea and C. Alenka NegreteA&A, 570 (2014) A96DOI: https://doi.org/10.1051/0004-6361/201423975