Follow-up observations of extremely metal-poor stars identified from SDSS D. S. Aguado, C. Allende Prieto, J. I. González Hernández, R. Carrera, R. Rebolo, M. Shetrone, D. L. Lambert and E. Fernández-Alvar A&A, 593 (2016) A10 Published online: 29 August 2016 DOI: 10.1051/0004-6361/201628371