Extremely metal-poor stars .1. Spectroscopic data

We have obtained high-resolution spectroscopic material for 23 stars with extremely low metal abundances, nine of which have [Fe/H] less than -3.0. We present here equivalent width measurements and compare them with literature values, where they exist. Atomic log gf-values are also tabulated. For several of the most metal-poor stars, we combine the line lists of different investigators to provide the most comprehensive data compilation available. These measurements will be used in companion papers as the basis for an analysis of the abundances of these stars and a discussion of their significance for Galactic chemical enrichment.