This study deals with the analysis of cited references in Web of Science (WoS) to e-prints on arXiv. Created in 1991, arXiv accelerated the scholarly communication and developed into a well-established e-print repository that functions as an essential access point to the latest research in physics, astrophysics, mathematics, computer science and related fields. Authors evidently rely on arXiv full texts and refer to them in their own research papers. These cited references to arXiv that represent the acceptance of e-prints in journals and series indexed in WoS are tackled in this paper. A total of 900,000 cited references to arXiv have been identified for the 19912013 period. Object of investigation is on the one hand the set of cited references to arXiv, and on the other hand the set of papers in WoS that cite arXiv. Among other things, the paper illustrates that citations to arXiv peak in the year after submission and drop rapidly. The geographical distribution of authorship citing arXiv in their papers shows that authors from the US, Germany, GB, France and Italy rely heavily on arXiv. The paper identifies "arXiv-friendly" journals where the majority of articles refer to arXiv.