oak for sale or trade

This is a historic bonsai. It is a European oak, Quercus robur, collected in Germany in 1981. It was once the best oak bonsai in Germany. I acquired it in 1991. It was featured in a couple of articles. See
 http://walter-pall.de/oakseuropean_oak_nr__2.jpg.dir/index.html

Two years ago the tree lost the back branch. I have decided to put the tree up for sale or trade.