Nothing happens when I click on the "Census 2010 based puma maps" link at sda.usa.ipums.org/us2012e/doc/nes.htm

Unfortunately, the Codebook within the SDA cannot display websites external to IPUMS. In this case, the link you are referring to leads to the Census website. You can, however, still right-click the link and open it in a new tab or new window. Alternatively, you can use the online Variables pageto find that variable. The content there is the same as the codebook, but external links will work.

I hope this helps.

Perfect! Thanks for the quick, careful response. Todd