He mentioned Apple, Microsoft, Monsanto and a european cartel called “Schienenfreunde” (friends of railroads). I pointed out that there is in fact competition in those areas, that these corporations are improving their products but that their “monopoly” is caused by Intellectual Property laws. Hence, they are not operating in the free market. After a little research I found out that the cartel was broken up because one company undercut the fixed price. So I asked him again to name a company that has achieved a monopoly over a long term without help from the government and he was unable to name one… Anyway, thanks for the resources!