Yes: there are databases. However, as also elaborated in the paper, the issue is not merely about providing wrong (including nonexistent) references but also a

Yes: there are databases. However, as also elaborated in the paper, the issue is not merely about providing wrong (including nonexistent) references but also about factual correctness of the references or not giving references when needed. I don't know whether these and other aspects of Perplexity's (or CoPilot's) references have been evaluated.