sentences:  Similar to tubes transitions intersubband transitions are forbidden for armchair graphene nanoribbons.Despite different selection rules in single wall armchair carbon nanotubes and zigzag graphene nanoribbons a hidden correlation of the absorption peaks is predicted.The correlation of the absorption peaks in tubes and ribbons should take place when the number of atoms in the tube unit cell formula_8 is related to the number of atoms in the zigzag ribbon unit cell formula_9 as follows