The distinction between works and expressions would seem to be at the heart of the difficulties in resurfacing reworks. As soon as you are able to group all expression numbers under a single work number, you can let transparency handle the rest. As far as I am aware there is currently only the most tenuous process available for linking expression numbers under a given work number. If any progress is to be made, the first step must be remedying this. The difficulty is that accurately and comprehensively assigning work numbers to expression numbers is non-trivial. What I would suggest then is this. Add a work number field to the PG database and default it to the expression number. Define the "correct" work number to be the lowest expression number of all the expressions that relate to that work. Then use some form of collaborative editing system (wiki page, google docs, web app, whatever...) to allow reporting of errors in the format: 41445=84 This wouldn't be comprehensive, of course, but it would allow capture of those works that people care about enough to report. Only a first small step of course, but that is how journeys begin. Regards Jon