It all comes down to the rules setup by hub pages. However my marketing business partner and I have discovered that it is about 2 links max per hub.
This refers to links outside of hub pages. Whereas if you are linking to other "relevant hub articles" then you can add as many as needed to make the point.
Just be careful and you won't be penalized much if you stray.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.