Differences in 9mm ammo?

I kind of feel dumb to ask this question, especially with my military background, but I bought a ruger p95, and was looking for some surplus ammo for it, and as I was looking I stumbled across the following descriptions of ammo: 9mm steyer, 9mm flobert, 9mm luger, 9mm largo and 9mm. I called a friend who has a lot of experience, and he was at a loss. what is the difference between those, or are they all safe to shoot in a 9mm??? best answer will be awarded!