Where can I get some information on white african mercenaries?

I love the movie Blood Diamond, Ive seen it several times and Im really fascinated by the character leo dicaprio plays; danny archer. Dicaprio said he talked to alot of actual african mercenaries like that for information on his character. Im very curious on those mercenaries, Id like to know more about them, those south african and white african mercenaries type of guys. I tried to find more information on them, but couldnt find nothing. Does anyone know where to find some more information on these guys. I would love to read an interview with one of them. Find out some more about these kind of people. Anyone who can help me with that ?