diff --git a/19-Spatial-Analysis-and-Cartography/rtree-spatial-indexing.ipynb b/19-Spatial-Analysis-and-Cartography/rtree-spatial-indexing.ipynb
index 7b28232..11683c2 100644
--- a/19-Spatial-Analysis-and-Cartography/rtree-spatial-indexing.ipynb
+++ b/19-Spatial-Analysis-and-Cartography/rtree-spatial-indexing.ipynb
@@ -6,7 +6,7 @@
    "source": [
     "# r-tree spatial indexing with Python and geopandas\n",
     "\n",
-    "This demo uses [OSMnx](https://github.com/gboeing/osmnx) and [geopandas](http://geoffboeing.com/2014/09/using-geopandas-windows/) to quickly find points within a polygon using an r-tree spatial index"
+    "This demo uses [OSMnx](http://geoffboeing.com/2016/11/osmnx-python-street-networks/) and [geopandas](http://geoffboeing.com/2014/09/using-geopandas-windows/) to quickly find points within a polygon using an r-tree spatial index"
    ]
   },
   {