I think Wikipedia really needs a central bibliography,
because there are many books who are used in more than
one article, some in dozens or even more.
Currently, a book reference is done this way:
<ref>[[Istvan Vasary]] (2005) ''Cumans and Tatars'',
[[Cambridge University Press]]. ISBN 123546958695,
page 22</ref>
with a central bibliography, it would be like this;
<book n="Cumans and Tatars" p="22"/>
and the book database would fill in the details in the
page displayed to the viewer.
I suggest that we use the name instead of the ISBN, because
it can be seen more clearly in the text, when reading the
wiki-text. Also, there are many books (especially older
books, but not only), which have no ISBN number and some
which have many different editions with different ISBNs.
There is still the problem with two books with the same title,
in which case we need to add the author, too, for disambiguation,
but I think this problem is less on the kind of books we use for
reference. Shorter titles are used especially for fiction.
There could be some benefits for having a central bibliography,
other than not having to copy-paste the publishing house/ISBN,
like knowing which articles refer to a certain book.