Significant in the differences between Hart and Kelsen was the emphasis on the British version of positive law theory which Hart was defending as opposed to the Continental version of positive law theory which Kelsen was defending. This was studied in the University of Toronto Law Journal in an article titled "Leaving the Hart-Dworkin Debate" which maintained that Hart insisted in his book "The Concept of Law" on the expansive reading of positive law theory to include philosophical and sociological domains of assessment rather than the more focused attention of Kelsen who considered Continental positive law theory as more limited to the domain of jurisprudence itself.