We all know (or we should know) that Authors Tutorial says: The item must NOT include any brand names, logos or trademarks.
But is there any place where you can actually check what is and what isn’t trademark/brandname? I was trying to search for such a database in Google there appears to be some, but interesting enough none of them returned any results for Coca Cola nor Nike or other well known brands. That made me doubt their reliability.
I don’t think that this exists in a worldwide scale. What I know is that when you want to register some brand internacionally you have to send it to some international organization for approval.