And here's one nearby in modern-day Sweden https://www.forskning.se/2016/11/07/valbevarade-spar-fran-st...

Sorry can't find much in English or much about it at all. Iirc I once chanced upon a meet-some-archaeologists stall set up in a town square nearby and listened to an archaeologist talking about it and showing fancy maps and diagrams that really excited me, but none of that seems to have spilled online.