Manuel Kellerbauer is a Member of the Legal Service of the European Commission, and lectures on competition law at the Europa Institute of Saarland University.Marcus Klamert is a Member of the Legal Service at the Federal Chancellery of Austria and a senior lecturer at the Vienna University of Economics and Business. He is the author of The Principle of Loyalty in EU Law (OUP, 2014).Jonathan Tomkin is a Member of the Legal Service of the European Commission, an affiliated Member of the Institute of European Law, KU Leuven, and co-authored THE EU Citizenship Directive (with E Guild and S Peers, OUP, 2014) Less