RefTeX is a reference management software package designed for use with Emacs and BibTeX. It can cooperate with the popular AUCTeX package. It is distributed under the GNU General Public License. It was originally written by Carsten Dominik, the author of org-mode and CDLaTeX. Since Emacs 24.3 it is maintained inside the Emacs repository.
References
RefTeX Wikipedia(Text) CC BY-SA