Here you can find an interactive map with all the employment centers identified in the paper in the US Metropolitan Statistical Areas. Zoom in and out or go to full-screen mode for a more immersive experience with the buttons on the upper left of the map. By default, only the MSA boundaries and the polygons for 2010 are displayed. However, it is easy to turn on and off the layers for the rest of the years using the "Visible layers" drop-down menu in the upper-right corner of the map.
Below the overall map, you can find a zoom into the following cities:
If you are interesting in downloading the geojson files with polygon data for the centers, you can do so at the Github repository. Enjoy!