The bold part was not in the PNT. In his original post he was only asking about books or articles that would have more precise info.
Theres little bits of data here and there, can anyone point me to a book or article that seems to have more precise and conclusive data on it..
The bold seems to be what he has found so far.
He isn't really wanting a debate, just direction on the web. So no one should be arguing with him, just directing him.