Vargyas's work may well be incorporated in his humungous book, which I have at home.

https://www.libri.hu/konyv/folk-music-of-the-hungarians.html

I think it was a free download once but I can't now trace it.

BTW that long-range influence-tracing does have parallels. Look at Carlo Ginzburg's Ecstasies, which follows quite unrelated ideas over a similar path and timescale to what Lloyd does with that song.