Update README.md

README.md

@@ -4,12 +4,13 @@ See map [here](http://bl.ocks.org/simzou/6459889)
 
 See code [here](https://github.com/simzou/nielsen-dma/)
 
-###Credits
+### Credits
 
 * Map adapted from Mike Bostock's [map example](http://bl.ocks.org/mbostock/2206590)
-* Topojson made by converting shapefile from [here](http://geocommons.com/overlays/306767) to topojson via [Mike Bostock's instructions](http://bost.ocks.org/mike/map/)
+* Original topojson made by converting shapefile from [here](http://geocommons.com/overlays/306767) to topojson via [Mike Bostock's instructions](http://bost.ocks.org/mike/map/)
+     * Shapefile link is dead, an archived Geojson from Geocommons can be found [here](https://raw.githubusercontent.com/geoiq/gc_data/master/datasets/998.geojson)
 * Nielsen rank and TV data via [tvb](http://www.tvb.org/media/file/TVB_Market_Profiles_Nielsen_Household_DMA_Ranks2.pdf)
 
-###Notes
+### Notes
 
 * Some areas are shaped really strangely (such as a slice of Nevada being part of the Denver media market) but that is really how they are divided