Well, Tesla really was a Serbian - his father was in fact, a Serbian Orthodox priest, so the documentation on this is clear.

Of course, since he was born into the Austro-Hungarian Empire, and studied in Graz, we might as well let the Austrians take credit, as the Austrians really need it (what's Austria's greatest accomplishment? convincing the world that Mozart is Austrian, and Hitler is German!)

But really, he did his best work as an American, so USA! USA! USA! :)