(Re)Initialize BibTeX buffers.
Visit the BibTeX files defined by `bibtex-files' and return a list
of corresponding buffers.
Initialize in these buffers `bibtex-reference-keys' if not yet set.
List of BibTeX buffers includes current buffer if CURRENT is non-nil.
If FORCE is non-nil, (re)initialize `bibtex-reference-keys' even if
already set. If SELECT is non-nil interactively select a BibTeX buffer.
When called interactively, FORCE is t, CURRENT is t if current buffer uses
`bibtex-mode', and SELECT is t if current buffer does not use `bibtex-mode',
(fn &optional CURRENT FORCE SELECT)