Dialogue: Canadian Philosophical Review
According to the standard account of Nicholas' views,his scepticism is constrained by his commitment to the law of non-contradiction as a basis for certain truth. Such an account fails to distinguish the (early and later) views found in the "Leters to Bernard" and the "Exigit Ordo" the latter clear rejects the law of non-contradiction and propounds a full fledged scepticism.
Groarke, Leo. (1984). On Nicholas of Autrecourt and the Law of Non-Contradiction. Dialogue: Canadian Philosophical Review, 23 (1), 129-134.