Hi!
For example "I want to know the number of
statements on an average with
dead external reference links".
Since there are over a million links in references, you probably may
want to use dump - either JSON or RDF, and looking for references there.
It would be relatively easy to find those in reference statements.
However, checking a million links might require some careful planning :)
--
Stas Malyshev
smalyshev(a)wikimedia.org