This ties in with my previous reply... from an article in 'The Sunday Times':

I looked back to see if there was a link to the article but I must have missed it. Do you have it still?

Thanks too for the link about the plagiarism issue. Yes, it surprises me that it seems to occur on such a regular basis. I guess in such a large group of writers it's easier for people to think it might go undetected. Kind of interesting in the way it sheds light on the issue of derivative status.