The firt citation for marriage data is listed as "Hajnal (RH31)", but links to a seemingly unrelated WorldCat search. The second citation is to "Kaplan (RH03)", which I was able to track down on sci-hub. It is a broad theory of human evolution that doesn't appear to mention the Yangtze Basin or China.
Another citation is to "[RH109] Model-supplied gap-fill (Claude Fable 5 and Claude Opus 5, 2026-08-05). Bounds and items written to close gaps no dataset we hold covers. Not a published work: see each row's `basis` for its stated reason. (2026)" -- this is an interesting way to describe having an LLM hallucinate something for you.
Please stop making vibe-coded websites -- it is not useful to provide incorrect facts. You are polluting the commons with garbage.