You literally ask it for the paper(s) and author(s) associated, put them into Google Scholar, and go read them. If it hallucinates a paper title, Scholar will usually find the relevant work(s) anyways because the author and title are close enough. If those fail, you Google some of the terms in the explanation, which is generally much more successful than Googling the original query. If you can't find anything at all, then it was probably a total hallucination, and you try the prompt a different way. That probably happens less than 1% of the time, however.

I mean, it's all just kind of common sense how to use an LLM.