Peculiar emission line spectra of core extremely red BOSS quasars at z∼2–3: orientation and/or evolution?M. Villar Martín, M. Perna, A. Humphrey, N. Castro Rodríguez, L. Binette, P. G. Pérez González, S. Mateos and A. Cabrera LaversA&A, 634 (2020) A116DOI: https://doi.org/10.1051/0004-6361/201937086