Update links in index.md

resources/index.md

@@ -88,13 +88,13 @@ by Houtan Bastani
 <p class="indent" markdown="1">
 <i class="fas fa-file-pdf"></i> [Guide to Specifying
 Observation Equations for the Estimation of DSGE
-Models](https://sites.google.com/site/pfeiferecon/Pfeifer_2013_Observation_Equations.pdf?attredirects=0),
+Models](https://drive.google.com/file/d/1r89OU5OE3CBa6tOlj6l3hNVWEaRH5Anv/view?usp=sharing),
 by Johannes Pfeifer
 </p>
 
 <p class="indent" markdown="1">
 <i class="fas fa-file-pdf"></i> [Introduction to Graphs in
-Dynare](https://sites.google.com/site/pfeiferecon/Pfeifer_2014_Dynare_graphs.pdf?attredirects=0),
+Dynare](https://drive.google.com/file/d/1DO1OK5AKLWfcJX49ZPCGo58Ni2LdERw4/view?usp=sharing),
 by Johannes Pfeifer
 </p>