  In a scientific publishing environment that is increasingly moving online,
identifiers of scholarly work are gaining in importance. In this paper, we
analysed identifier distribution and coverage of articles from the discipline
of quantitative biology using arXiv, Mendeley and CrossRef as data sources. The
results show that when retrieving arXiv articles from Mendeley, we were able to
find more papers using the DOI than the arXiv ID. This indicates that DOI may
be a better identifier with respect to findability. We also find that coverage
of articles on Mendeley decreases in the most recent years, whereas the
coverage of DOIs does not decrease in the same order of magnitude. This hints
at the fact that there is a certain time lag involved, before articles are
covered in crowd-sourced services on the scholarly web.
