Jack, there is indeed a reference to László Fehér in this thread, but I can't see any text previous to the one I posted.

In any event, thanks for reminding me of the Encyclopaedia of Hungarian Ethnology and Folklore. I Picked a copy up in a charity shop once for £4-00, which was amazingly cheap considering the size of the thing and the weightiness of the content.

There's also Ninon Leader's book on Hungarian Folk Ballads of course, which I'm almost certain contains a study of LF.