Stanley L. Paulson (Washington University in Saint Louis - School of Law) has posted How Merkl's Stufenbaulehre Informs Kelsen's Concept of Law (Revus - Journal for Constitutional Theory and Philosophy of Law, 21, 2013, 29-45) on SSRN. Here is the abstract:
For many reasons, it seems that Kelsen’s legal theory uses two competing concepts of law, one turning on coercion, the later concept reflecting the process of law creation. But this is not the case. Actually the two concepts are incorporated into a single concept of law. Here we face with two points of view which are combined in a single concept of law that reflects both process and coercion. In such an enterprise, the Stufenbaulehre and the conceptual machinery that can be drawn from it is central to our understanding of Kelsen’s concept of law.
As always, Pauson on Kelsen is recommended!