How to convert kg cm2 to n mm2?

You cannot. A kg is a measure of mass, a Newton is a measure of force. The two measure different things and any attempt to convert from one to the other if flawed.

Measuring them per unit area (cm^2 or mm^2) does not change that.

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.