I've noticed some duplicate items. I deleted one where there was a duplicate in the title (deleting one with a typo-a space missing in the title). In general, it's difficult to decide which item to keep, because while the titles and gist of the metadata may match, there are differences. For instance, look at "A content-driven reputation system for the Wikipedia"--one has the correct proceedings title, the other has an abstract. So there's some work to merge items and get the best result. Maybe choosing based on repository makes sense? i.e. trust ACM over unAPI? -Jodi