There are more and more references to Per Martin Tvengsberg and his books on Wikipedia and more to come.  Just to give you a few examples of encyclopedic content, take a look at: http://en.wikipedia.org/wiki/History_of_agriculture, http://en.wikipedia.org/wiki/Iron_age, http://en.wikipedia.org/wiki/Vikings.  References to Per Martin Tvengsberg and his books.  But if Wikipedia is better off without info about him I have no strong feelings about this. Follow the Wikipedia policy.