Peter Langford, Edge Hill University, and Ian Bryan, Lancaster University, have posted Kelsen, Weber and the Free Law Movement, which appears in Jahrbuch für Soziologiegeschichte 2020, , 113-145:
The article concentrates upon the emergence, in the first decade of the twentieth century, of the distinctive German language tradition of the sociology of law and, in particular, the early work of Hermann Kantorowicz, as the exemplary representative of the Free Law Movement (Freirechtsbewegung). The Free Law Movement challenges the preceding conception of judicial decision-making of Begriffsjurisprudenz, initiating the wider question of the status and foundation of a theory of law. The challenge is considered through the engagement of Hans Kelsen and Max Weber with Kantorowicz, tracing the appropriation of the insights of the Free Law Movement for a Kelsenian pure theory of positive law and for a Weberian sociology of law.
--Dan Ernst. H/t: Legal Theory Blog