sentences:  He became member of the Royal Netherlands Academy of Arts and Sciences (KNAW) in 2000.In 2004 the KNAW entitled him with an academy professorship.The handbook "Constitutioneel Recht" (Constitutional Law, for which Kortmann received the Thorkbecke Prize in 1996), "Het staatsrecht van de landen van de Europese Unie" (Constitutional law of the Member States of the European Union), and "Het bestuursrecht van de landen der Europese Gemeenschappen" (Public Law of the Member States of the European Communities) are amongst his most important publications.