Reformat bib file

gipp.bib

@@ -1607,12 +1607,12 @@
 
 @inproceedings{GreinerPetter2019b,
   author    = {Greiner-Petter, Andr{\'{e}} and Ruas, Terry and Schubotz, Moritz and Aizawa, Akiko and Grosky, William and Gipp, Bela},
+  url       = {http://ceur-ws.org/Vol-2414/paper14.pdf},
   booktitle = {Proceedings of the 4rd Joint Workshop on Bibliometric-enhanced Information Retrieval and Natural Language Processing for Digital Libraries {(BIRNDL} 2018) co-located with the 42nd International {ACM} {SIGIR} Conference on Research and Development in Information Retrieval {(SIGIR} 2019), Paris, USA, July 25, 2019.},
   date      = {2019-07},
   keywords  = {preprint,SchubotzCV},
   preprint  = {https://arxiv.org/pdf/1905.08359},
   title     = {Why Machines Cannot Learn Mathematics, Yet},
-  url       = {http://ceur-ws.org/Vol-2414/paper14.pdf}
 }
 
 @article{GreinerPetter2019,