As has been pointed out on the relevant talk page, having written something (if we choose to believe an unidentified pseudonymous user) is not necessarily sufficient to establish ownership. CoolCat claimed that text was prepared for a large offline (i.e. print) distribution. We have no way of knowing if that was work-for-hire, for example.
True. We have no way of knowing that anything that anyone writes for wikipedia really belongs to them. All we can do is assume that they are telling the truth when they claim it's thier own work.
When it comes to copyright problems, all one has to do is anonymously claim "I wrote it" when it is found to have been published earier elsewhere? That can't be right.
This sort of thing could easily be sorted out though. We could contact the publishers directly "Do you give permission for this material to be on Wikipedia?"
Theresa