Here a few links to some pics and vids of a very rare 500cc GP machine the Librenti V4 500cc two stroke. In the pic above you see Marco Papa and the 1992 bike. These bikes were made by Giancarlo Librenti who died in 1993 at the age of 56. Librenti is one of the more illusive Italian makes, just like VRP. First you had Cagiva and then Paton and after that the small ones like Librenti and VRP.
For more pics see
Librenti
Start up of a Librenti
Part 1
Part 2