fix invalid char

gipp.bib

@@ -1756,8 +1756,8 @@
 }
 
 @inproceedings{GreinerPetter2020,
-  author    = {Greiner-Petter, Andr{\\textquoteright{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{e}} and Schubotz, Moritz and M\"{u}ller, Fabian and Breitinger, Corinna and S. Cohl, Howard and Aizawa, Akiko and Gipp, Bela},
-  booktitle = {Proceedings of The Web Conference 2020 (WWW \textquoteright{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}20), April 20--24, 2020, Taipei, Taiwan},
+  author    = {Greiner-Petter, Andr{\'{e}} and Schubotz, Moritz and M\"{u}ller, Fabian and Breitinger, Corinna and S. Cohl, Howard and Aizawa, Akiko and Gipp, Bela},
+  booktitle = {Proceedings of The Web Conference 2020 (WWW'20), April 20--24, 2020, Taipei, Taiwan},
   core      = {0;Core Rank A*;http://portal.core.edu.au/conf-ranks/1548/},
   date      = {2020-04},
   doi       = {10.1145/3366423.3380218},