German military cemetery, Glencree

I had no idea that there was a German military cemetery a few miles away when I moved to South Dublin.
Being a total history nut, I had to go and visit it. It is small, but very well-kept. A lot of the graves just say "Unbekannt" or Ein (or) Zwei Deutsche Soldaten on the headstones.
Although it is certainly not a tourist attraction, it would have been nice to have had some sign there telling you about the history behind it; we were neutral after all, so how did these soldiers end up dying here? I'm sure there is a book about it somewhere...