In 1911, he achieved his habilitation (license to give university lectures) in public law and legal philosophy, with a thesis that became his first major work on legal theory, "Hauptprobleme der Staatsrechtslehre entwickelt aus der Lehre vom Rechtssatze" ("Main Problems in Theory of Public Law, Developed from Theory of the Legal Statement"). In 1919, he became full professor of public and administrative law at the University of Vienna, where he established and edited the "Zeitschrift für öffentliches Recht" (Journal of Public Law). At the behest of Chancellor Karl Renner, Kelsen worked on drafting a new Austrian Constitution, enacted in 1920. The document still forms the basis of Austrian constitutional law. Kelsen was appointed to the Constitutional Court, for his lifetime. Kelsen's emphasis during these years upon a Continental form of legal positivism began to further flourish from the standpoint of his law-state monism, somewhat based upon the previous examples of Continental legal positivism found in such scholars of law-state dualism such as Paul Laband (1838–1918) and Carl Friedrich von Gerber (1823–1891).