citation and figure update

references.bib

@@ -110,11 +110,13 @@
 	  url={https://ge.in.tum.de/publications/2020-iclr-holl/},
 }
 
-@inproceedings{holl2021pg,
-	  title={Physical Gradients and Scale-Invariant Physics for Deep Learning},
+@article{holl2021pg,
+	  title={Scale-Invariant Physics for Deep Learning},
 	  author={Holl, Philipp and Koltun, Vladlen and Thuerey, Nils},
-	  booktitle={arXiv:2109.15048},
-	  year={2021},
+	  journal={Advances in Neural Information Processing Systems},
+	  volume={35},
+	  pages={5390--5403},
+	  year={2022}
 	  url={https://arxiv.org/abs/2109.15048},
 }