message: doc: added bibtex citation
diff: @@ -60,3 +60,17 @@ request); for missing features please contact us via email at
  Join our [mailing list](https://groups.google.com/d/forum/openimagedenoise/) to
  receive release announcements and major news regarding Intel Open Image Denoise.
  +Citation
  +--------
  +
  +If you use Intel Open Image Denoise in a research publication, please cite the
  +project using the following BibTeX entry:
  +
  +```bibtex
  +@Misc{OpenImageDenoise,
  + author = {Attila T. {\'A}fra},
  + title = {{Intel\textsuperscript{\textregistered} Open Image Denoise}},
  + year = {2020},
  + note = {\url{http://www.openimagedenoise.org/}}
  +}
  +```
  \ No newline at end of file
  