add arXiv link

Author: yunjunz

README.md

@@ -1,6 +1,6 @@
 ## Jupyter Notebooks for:
 
-Yunjun, Z., Fattahi, H., Pi, X., Rosen, P., Simons, M., Agram, P., & Aoki, Y. (2022). Range Geolocation Accuracy of C/L-band SAR and its Implications for Operational Stack Coregistration. _IEEE Trans. Geosci. Remote Sens._, doi:[10.1109/TGRS.2022.3168509](https://doi.org/10.1109/TGRS.2022.3168509).
+Yunjun, Z., Fattahi, H., Pi, X., Rosen, P., Simons, M., Agram, P., & Aoki, Y. (2022). Range Geolocation Accuracy of C/L-band SAR and its Implications for Operational Stack Coregistration. _IEEE Trans. Geosci. Remote Sens._, doi:[10.1109/TGRS.2022.3168509](https://doi.org/10.1109/TGRS.2022.3168509), [arXiv](https://doi.org/10.31223/X5F641).
 
 ### Data ([Zenodo](https://zenodo.org/record/6360749))