"Aforementioned" vs. "aforesaid"
Solution 1:
They make you sound like a lawyer, and I wouldn’t use either. Try The principle (I have) already mentioned or The principle referred to above.
Solution 2:
I find the supercited aforementioned to be way too complicated. It tends to raise eyebrows, and not just superciliously, either. More like supersilliest, perhaps.
You could just call it the stated principle, or (unless this form bothers you too much), the above principle.
Just don’t use supercited. :)