Antonio Zoli Shotgun, any more information or sources of info?

http://imgur.com/a/p7AXr

My friend has an Antonio Zoli shotgun that his father has had for years. We tried doing some research and didn't find much. We found out that there are some Antonio Zoli guns that are worth oodles of money and others are not worth much. Any info is appreciated. I tried to get pictures of the proofs. I'll try to find more pictures later. They're on my buddies phone.