Glider mid-airs in Switzerland

I'm looking for information on glider-glider collisions in Switzerland
over the last ten years. I have looked at the website of the BFU:

http://www.bfu.admin.ch/en/dokumenta...hte_suchen.htm

Searching for aircraft type Glider. However in the results I've only
found one mid-air - between a DG500 and a ASW20 on 29 July 2003.

I was under the impression that there had been a series of fatal
glider-to-glider collisions in Switzerland. I might be reading the
website incorrectly or looking in the wrong place.

Can a resident, or perhaps a native speaker of an appropriate
language, tell me if there were more serious mid-airs, and provide a
source of information? Specifically what I am looking for is the
number of serious glider-to-glider collisions in Switzerland for each
of the last ten years.


Dan