At last, thanks to Professors Edelman and George at Vanderbilt, we have the answer! Professor Edelman writes:
We had to search by hand through multiple data bases to track down co-authors of co-authors of Sunstein for our project and we really need more eyes on the results to ensure that we got everyone who belongs. We are hoping that the more people who look at the paper, the more reliable the data will be.
E-mail Professor Edelman with corrections.