Your bug report

#19205: 24.3.1; bibtex entry containing a single ( character can not be cited anymore

which was filed against the auctex package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 19205@debbugs.gnu.org.

-- 
19205: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=19205
GNU Bug Tracking System
Contact help-debbugs@gnu.org with problems