List of Publications

Monographs 

• European Migration Law (OUP, 2023), forthcoming.

Editorial Responsibility

• Member of the Management Board of the European Papers – Carnets européens – Cuadernos Europeos – Quaderni europei (since 2020).
• EU Immigration and Asylum Law. Article-by-Article Commentary, 3rd edition (C.H. Beck/Hart/Nomos, 2022), together with Kay Hailbronner.
• Reforming the Common European Asylum System. Opportunities, Pitfalls, and Downsides of the Commission Proposals for a New ‘Pact’ on Migration and Asylum (Nomos, 2022), together with the Odysseus Academic Network.
• Research Handbook on European Union Citizenship Law and Policy (Elgar, 2022), together with Dora Kostakopoulou.
• Member of the Advisory Board von European Law Open (since 2022).
• Special Series of the EU Immigration and Asylum Law Blog of the Odysseus Academic Network: New Pact on Migration And Asylum with 19 blogposts written by experts from across Europe, published between September 2020 and March 2021.
• Questioning EU Citizenship. Judges and the Limits of Free Movement and Solidarity in the EU (Bloomsbury/Hart, 2017).
• Special Issue: ‘Searching for Solidarity in the EU Asylum and Border Policies. Constitutional and Operational Dimensions’, Maastricht Journal of European and Comparative Law 24 (2017), Issue 5, together with Evangelia (Lilian) Tsourdi.
• Book Review Editor of the European Law Journal – Review of European Law in Context (2006–19).
• Member of the International Scientific Advisory Board des Scientific Committee Diritto, Immigrazione e Cittadinanza (since 2018).
• EU Immigration and Asylum Law. Commentary, 2nd edition (C.H. Beck/Hart/Nomos, 2016) together with Kay Hailbronner.
• Rights of Third-Country Nationals under EU Association Agreements. Degrees of Free Movement and Citizenship (Brill Nijhoff, 2015), together with Margarite Zoeteweij-Turhan.
• Europe – A Continent of Immigration? Legal Challenges in the Construction of European Migration Policy. Europe: Un continent d'immigration? Défis légaux juridiques dans la construction de la politique européenne de migration (Bruylant, 2011), together with Francis Snyder.
• Peer Review amongst others for: European Law Journal, European Law Online, European Papers, European Constitutional Law Review, European Journal of Migration and Law, International Journal of Refugee Law, Journal of European Public Policy, Journal of Ethnic and Migration Studies, International Migration, Maastricht Journal of European and Comparative Law, European Law Review.

• ‘Supranational Courts in Europe. A Moderately Communitarian Turn in the Case Law on Immigration and Citizenship’, Journal of Ethnic and Migration Studies 47 (2021), 4534–51.
• ‘European Integration: Quo vadis? A Critical Commentary on the PSPP Judgment of the German Federal Constitutional Court of May 5, 2020’, International Journal of Constitutional Law 19 (2021), 188–207 (together with Jürgen Basedow, Jan Dietze, Stefan Griller, Manuel Kellerbauer, Marcus Klamert, Luigi Malferrari, Tibor Scharf, Dominik Schnichels and Jonathan Tomkin).
• ‘The End of Human Rights Dynamism? Judgments of the ECtHR on “Hot Returns” and Humanitarian Visas as a Focal Point of Contemporary European Asylum Law and Policy’, International Journal of Refugee Law 32 (2020), 569–96.
• ‘Friendly Takeover, or: the Power of the “First Word”. The German Constitutional Court Embraces the Charter of Fundamental Rights as a Standard of Domestic Judicial Review’, European Constitutional Law Review 16 (2020), 187–212.
• ‘Schengen and Free Movement Law During the First Phase of the Covid-19 Pandemic: Of Symbolism, Law and Politics’, European Papers 5 (2020), 1143–70, together with Jonas Bornemann.
• ‘A Bird’s Eye View on ECJ Judgments on Immigration, Asylum and Border Control Cases’, European Journal of Migration and Law 21 (2019), 166–93.
• ‘Between “Administrative Mindset” and “Constitutional Imagination”. The Role of the Court of Justice in Immigration, Asylum and Border Control Policy’, European Law Review 44 (2019), 138–58.
• ‘Judicial Maintenance of the Sputtering Dublin System on Asylum Jurisdiction: Jafari, A.S., Mengesteab and Shiri’, Common Market Law Review 55 (2018), 549–68.
• ‘Searching for Solidarity in the EU Asylum and Border Policies: Constitutional and Operational Dimensions’, Maastricht Journal of European and Comparative Law 24 (2017), 605–21 (together with Evangelia (Lilian) Tsourdi).
• ‘The “Refugee Crisis” as a Challenge of Legal Design and Institutional Legitimacy’, Common Market Law Review 53 (2016), 1545–74.
• ‘Citizens and Foreigners in EU Law. Migration Law and Its Cosmopolitan Outlook’, European Law Journal 22 (2016), 296–316.
• ‘Towards a Contextual Conception of Social Integration in EU Immigration Law. Comments on P & S and K & A’, European Journal of Migration and Law 18 (2016), 89–111.
• ‘The Elusive Limits of Solidarity. Residence Rights of and Social Benefits for Economically Inactive Union Citizens’, Common Market Law Review 52 (2015), 17–50.
• ‘When Union Citizens turn into Illegal Migrants: the Dano case’, European Law Review 40 (2015), 248–61 = Current Law 6 (2015), 535–48.
• ‘Separation versus Fusion – or: How to Accommodate National Autonomy and the Charter? Diverging Visions of the German Constitutional Court and the European Court of Justice’, European Constitutional Law Review 9 (2013), 391–419.
• ‘EU Migration Policy and its Constitutional Rationale. A Cosmopolitan Outlook’, Common Market Law Review 50 (2013), 709–36.
• ‘Préserver le respect du droit dans la crise: la Cour de justice, le MES et le Mythe du déclin de la communauté de droit’, Cahiers de droit européen 48 (2012), 733–57 (together with Mattias Wendel).
• ‘Court of Justice of the European Union: Case C-34/09, Gerardo Ruiz Zambrano v. Office national de l’emploi (ONEm), Judgment of 8 March 2011’, Common Market Law Review 48 (2011), 1253–70 (together with Kay Hailbronner).
• ‘The Intergovernmental Constitution of the EU’s Foreign, Security & Defence Executive’, European Constitutional Law Review 7 (2011), 453–80.
• ‘In the Name of Sovereign Statehood: A Critical Introduction to the Lisbon Judgment of the German Constitutional Court’, Common Market Law Review 46 (2009), 1795–1822.
• ‘National Report: Germany. Administration Without Frontiers? European Migration Law’, European Review of Public Law 21 (2009), 253–72.
• ‘Respect for Private and Family Life under Article 8 ECHR in Immigration Cases: A Human Right to Regularise Illegal Stay?’, International and Comparative Law Quarterly 57 (2008), 87–112.
• ‘The Political Character of Supranational Differentiation’, European Law Review 31 (2006), 781–99.
• ‘Beyond Parliament’s Reach? The Role of the European Parliament in the Common Foreign and Security Policy’, European Foreign Affairs Review 11 (2006), 109–27.
• ‘United in Diversity’ – The Integration of Enhanced Co-operation into the European Constitutional Order”, German Law Journal 6 (2005), 1731–48.
• ‘The Barroso Drama: Pöttering and Schulz Take Over – Action and Inaction of National Politics in the Making of the Barroso Commission’, European Constitutional Law Review 1 (2005), 203–10.
• ‘Reforming Europe’s Common Foreign and Security Policy’, European Law Journal 10 (2004), 5–22.
• ‘Charter of Fundamental Rights: Competition or Consistency of Human Rights Protection in Europe?’, in: Finnish Yearbook of International Law XI (Den Haag: Kluwer, 2002), pp. 11–36.
• ‘A New Institutional Balance for European Foreign Policy?’, European Foreign Affairs Review 7 (2002), 369–400 (together with Ingolf Pernice).
• ‘The Schengen Law: A Challenge for Legal Accountability in the European Union’, European Law Journal 8 (2002), 218–45.

• ‘Institutional and Constitutional Framework’, in: Evangelia (Lilian) Tsourdi and Philippe De Bruycker (eds.), Research Handbook on EU Migration and Asylum Law (Elgar, 2022), pp. 57–78.
• ‘The Evolution of Citizens’ Rights in Light of the EU’s Constitutional Development’, in: Dora Kostakopoulou and Daniel Thym (eds.), Research Handbook on European Union Citizenship Law and Policy. Navigating Challenges and Crises (Elgar, 2022), pp. 49–69.
• ‘Introduction: Challenges and Crises of Union Citizenship’, in: ibid., pp. 1–11.
• ‘Never-Ending Story? Political Dynamics, Legislative Uncertainties, and Practical Drawbacks of the “New” Pact on Migration and Asylum’, in: Daniel Thym and Odysseus Academic Network (eds.), Reforming the Common European Asylum System (Nomos, 2022), pp. 11–32.
• ‘Secondary Movements: Improving Compliance and Building Trust among the Member States?’, in: ibid., pp. 129–48.
• ‘Differentiated Integration’, in: Sacha Garben and Laurence Gormley (eds.), Oxford Encyclopedia of EU Law (OUP, February 2022).
• ‘Constitutional Framework and Principles for Interpretation’, in: Daniel Thym and Kay Hailbronner (eds.), EU Immigration and Asylum Law. Article-by-Article Commentary, 3rd edition (C.H. Beck/Hart/Nomos, 2022), pp. 1-45.
  • ‘Legal Framework for Entry and Border Controls’, in: ibid., pp. 47-83.
  • ‘Legal Framework for EU Immigration Policy’, in: ibid., pp. 271-299.
  • ‘Long Term Resident Directive 2003/109/EC’, in: ibid., pp. 540-641.
• ‘Legal Framework for EU Asylum Policy’, in: ibid., pp. 1129-1176.
• ‘Article 71, 72, 77 and 78 TFEU’, in: Hermann-Josef Blanke and Stelio Mangiameli (eds.), Treaty on the Functioning of the European Union. A Commentary, Volume 1 (Springer, 2021), pp. 1405-1409, 1451-1489.
• ‘Deciphering the Role of Migration Law in the Social Construction of “Otherness”’, in: Moritz Jesse (ed.): European Societies, Migration, and the Law. The ‘Others’ amongst ‘Us’ (CUP, 2020), pp. 323-355.
• ‘Immigration after Brexit. Ironies and Challenges’, in: Ingolf Pernice/Ana Maria Guerra Martins (eds.): Brexit and the Future of EU Politics. A Constitutional Law Perspective (Nomos, 2019), pp. 185-197 (together with Mattias Wendel).
• ‘Supranational Differentiation and Enhanced Cooperation’, in: Takis Tridimas/Robert Schütze (eds.): The Oxford Principles of European Union Law (OUP, 2018), pp. 847-83.
• ‘The Evolution of Citizens’ Rights in Light of the EU’s Constitutional Development’, in: Daniel Thym (ed.): Questioning EU Citizenship (Bloomsbury/Hart, 2017), pp. 111-34.
• ‘Introduction: The Judicial Deconstruction of Union Citizenship’, in: Daniel Thym (ed.): Questioning EU Citizenship (Bloomsbury/Hart, 2017), pp. 1–14.
• ‘Conclusion: The Non-Simultaneous Evolution of Citizens’ Rights’, in: Daniel Thym (ed.): Questioning EU Citizenship (Bloomsbury/Hart, 2017), pp. 309–22 (together with Dora Kostakopoulou).
• ‘Frontiers of EU Citizenship. Three Trajectories and their Methodological Foundations’, in: Dimitry Kochenov (eds.): EU Citizenship and Federalism. The Role of Rights (CUP, 2017), pp. 705–30.
• ‘Competing Models for Understanding Differentiated Integration’, in: Bruno de Witte/Andrea Ott/Ellen Vos (eds.): Between Flexibility and Disintegration. The State of EU Law Today (Elgar, 2017), pp. 28–75.
• ‘Ambiguities of Personhood, Citizenship, Migration and Fundamental Rights in EU Law’, in: Loïc Azoulai/Ségolène Barbou des Places/Etienne Pataut (eds.): Constructing the Person. Rights, Roles, Identities in EU Law (Bloomsbury/Hart, 2016), pp. 111–31.
• ‘Family as Link. Explaining the Judicial Change of Direction on Residence Rights of Family Members from Third States’, in: Herwig Verschueren (eds.): Residence, Employment and Social Rights of Mobile Persons. On How EU Law Defines Where They Belong (Intersentia, 2016), pp. 11–38.
• ‘The Constitutional Dimension of Public Policy Justifications’, in: Panos Koutrakos/Niamh Nic Shuibhne/Phil Syrpis (eds.): Exceptions from EU Free Movement Law. Derogation, Justification and Proportionality (Bloomsbury/Hart, 2016), pp. 171–89.
• ‘Constitutional Framework and Principles for Interpretation’, in: Kay Hailbronner/Daniel Thym (eds.): EU Immigration and Asylum Law. Commentary, 2nd edition (C.H. Beck/Hart/Nomos, 2016), pp. 1–29 (together with Kay Hailbronner).
  • ‘Legal Framework for Entry and Border Controls’, in: ibid., pp. 31–51.
  • ‘Legal Framework for EU Immigration Policy’, in: ibid., pp. 271–99.
  • ‘Long Term Resident Directive 2003/109/EC’, in: ibid., pp. 427–519.
  • ‘Legal Framework for EU Asylum Policy’, in: ibid., pp. 1012–42 (together with Kay Hailbronner).
• ‘Constitutional Foundations of the Judgments on the EEC-Turkey Association Agreement’, in: Daniel Thym/Margarite Zoeteweij-Turhan (eds.): Rights of Third-Country Nationals under EU Association Agreements. Degrees of Free Movement and Citizenship (Brill Nijhoff, 2015), pp. 13–38.
• ‘Introduction: Free Movement between Membership and Partnership’, in: ibid., pp. 1–10 (together with Margarite Zoeteweij-Turhan).
• ‘Residence as de facto Citizenship? Protection of Long-Term Residence under Article 8 ECHR’, in: Ruth Rubio-Marin (ed.): Human Rights and Immigration (OUP, 2014), pp. 106–44.
• ‘Transfer Agreements for Pirates concluded by the EU – a Case Study on the Human Rights Accountability of the European Security and Defence Policy’, in: Panos Koutrakos/Achilles Skordas (eds.): The Law and Practice of Piracy at Sea (Hart, 2014), pp. 167–81.
• ‘Germany’, in: Ulla Neergaard/Catherine Jacqueson/Nina Holst-Christensen (eds.): Union Citizenship: Development, Impact and Challenges. The XXVI FIDE Congress in Copenhagen (DJØF, 2014), pp. 569–86 (together with Christoph Schönberger).
• ‘Towards “Real” Citizenship? The Judicial Construction of Union Citizenship and its Limits’, in: Maurice Adams/Johan Meeusen/Gert Straetmans/Henri de Waele (eds.): Judging Europe’s Judges. The Legitimacy of the Case Law of the European Court of Justice (Hart, 2013), pp. 155–74.
• ‘Towards International Migration Governance? The European Contribution’, in: Bart Van Vooren/Steven Blockmans/Jan Wouters (eds.): The EU’s Role in Global Governance. The Legal Dimension (OUP, 2013), pp. 289–305.
• ‘Attack or Retreat? Evolving Themes and Strategies of the Judicial Dialogue between the German Constitutional Court and the European Court of Justice’, in: Catherine van de Heyning/Maartje de Visser (eds.): Constitutional Conversations in Europe – Actors, Topics and Procedures (Intersentia, 2012), pp. 235–50.
• ‘Article 33 TEU (EU Special Representatives)’, ‘Article 38 (Political and Security Committee)’ and ‘Article 42 Abs. 7 (Mutual Defence)’, in: Hermann-Josef Blanke/Stelio Mangiameli (eds.): The Treaty on European Union. A Commentary (Springer, 2013), pp. 1089–94, 1147–58, 1222–31.
• ‘The Intergovernmental Branch of the EU’s Foreign Affairs Executive. Reflections on the Political and Security Committee (PSC) in the Age of the Lisbon Treaty’, in: Hermann-Josef Blanke/Stelio Mangiameli (eds.): The European Union after Lisbon. Constitutional Basis, Economic Order and External Action (Springer, 2011), pp. 517–32.
• ‘From Ultra-Vires-Control to Constitutional-Identity-Review: The Lisbon Judgment of the German Constitutional Court’, in: Ingolf Pernice/José María Beneyto (eds.): Europe’s Constitutional Challenges in the Light of the Recent Case Law of National Constitutional Courts. Lisbon and Beyond (Nomos, 2011), pp. 31–44.
• ‘Holding Europe’s CFSP/CSDP Executive to Account in the Age of the Lisbon Treaty’, in: José María Beneyto (ed.): La Unión europea como actor global. Las nuevas dimensiones de la política exterior europea (Biblioteca Nueva, 2011), pp. 21–48.
• ‘Introduction and Acknowledgments’, in: Daniel Thym/Francis Snyder (eds.): Europe – A Continent of Immigration? Legal Challenges in the Construction of European Migration Policy (Bruylant, 2011), pp. 1–12 (together with Francis Snyder).
• ‘Foreign Affairs’, in: Armin von Bogdandy/Jürgen Bast (eds.): Principles of European Constitutional Law, 2^nd edition (Hart, 2009), pp. 309–43.
• ‘Europa a varias velocidades: Las cooperaciones reforzadas’, in: José María Beneyto Pérez (ed.): Tratado de Derecho y Políticas de la Unión Europea, Tomo I. Desarrollo histórico y caracteres básicos de la Unión Europea. Naturaleza, valores, principios y competencias (Aranzadi, 2009), pp. 571–633.
• ‘Parliamentary Involvement in European International Relations’, in: Marise Cremona/Bruno de Witte (eds.): EU Foreign Relations Law: Constitutional Fundamentals (Hart, 2008), pp. 201–32.
• ‘Interregional Cooperation in Crisis Management: EU support for the AU, ASEAN and other Regional Organisations’, in: Steven Blockmans (ed.): The European Union and International Crisis Management: Legal and Policy Aspects (T.M.C. Asser, 2008), pp. 277–90.
• ‘Parliamentary Control of EU Decision-Making in Germany: Supportive Federal Scrutiny and Restrictive Regional Action’, in: Olaf Tans/Carla Zoethout/Jan Peters (eds.): National Parliaments and European Democracy. A Bottom-Up Approach to European Constitutionalism (Europa Law Publishing, 2007), pp. 47–72.
• ‘United in Diversity’ – The Integration of Enhanced Co-operation into the European Constitutional Order’, in: Philipp Dann/Michał Rynkowski (eds.): The Unity of the European Constitution (Springer, 2006), pp. 357–75.
• ‘Un nuovo equilibrio istituzionale nella politica estera europea’, in: Vincenzo Atripaldi/Roberto Miccú/Ingolf Pernice (eds.): Quale Costituzione per l’Europa. Consolidamento e innovazione costituzionale nel ‘secondo’ Trattato di Roma (Edizioni Scientifiche Italiane, 2006), pp. 487–512.
• ‘Reforming Europe's Common Foreign and Security Policy’, in: Francis Snyder (ed.): L'Union européenne et la gouvernance – The European Union and Governance (Bruylant, 2003), pp. 271–94.
• ‘European Constitutional Theory and the Post-Nice Process’, in: Mads Andenas/John Usher (eds.): The Treaty of Nice and Beyond – Enlargement and Constitutional Reform (Hart, 2003), pp. 147–80.

• ‘Border Closure and Visa Ban for Russians: Geopolitics Meets EU Migration Law’, EU Immigration and Asylum Law and Policy of 17 October 2022.
• ‘Illegality of Internal Border Controls: The Court of Justice feeds the Appetite for Legislative Reform’, EULawLive on 4 May 2022.
• ‘Temporary Protection for Ukrainians: the Unexpected Renaissance of “Free Choice”’, EU Immigration and Asylum Law and Policy on 7 March 2022.
• ‘Germany as a “Modern Country of Immigration”. Projects of the New Government on Migration’, EU Immigration and Asylum Law and Policy on 8 December 2021.
• ‘Muddy Waters: A Guide to the Legal Questions Surrounding “Pushbacks” at the External Borders at Sea and at Land’, EU Immigration and Asylum Law Blog on 6 July 2021.
• ‘Secondary Movements: Overcoming the Lack of Trust among the Member States?’, EU Immigration and Asylum Law Blog on 29 October 2020.
• ‘European Realpolitik: Legislative Uncertainties und Operational Pitfalls of the ‘New’ Pact on Migration and Asylum’, EU Immigration and Asylum Law Blog on 28 September 2020.
• ‘Travel Bans in Europe: A Legal Appraisal’, EU Immigration and Asylum Law and Policy on 18 March 2020 (Part I) & 19 March 2020 (Part II).
• ‘A Restrictionist Revolution? A Counter-Intuitive Reading of the ECtHR’s N.D. & N.T.-Judgment on “Hot Expulsions” at the Spanish-Moroccan Border’, EU Immigration and Asylum Law Blog on 17 February 2020.
• ‘Integration’, in: Philippe De Bruycker/Marie De Somer/Jean-Louis De Brouwer (eds.): From Tampere 20 to Tampere 2.0. Towards a new European consensus on migration (EPC, 2019), pp. 73-88 (together with Ilke Adam).
• ‘The German Migration Package: A New Deal on Labour Migration?’, EU Immigration and Asylum Law and Policy on 1 October 2019.
• ‘The Case Against an Autonomous “EU Rump Citizenship”’, in: Liav Orgad/Jules Lepoutre (eds.): Should EU Citizenship Be Disentangled from Member State Nationality?, RSCAS Research Paper No. 2019/24.
• ‘Legal Solution vs. Discursive Othering: The (Dis)Integrative Effects of Supranational Differentiation’, DCU Brexit Institute Working Paper No. 7/2018.
• ‘The Failure of Union Citizenship Beyond the Single Market’, in: Rainer Bauböck, Rainer (eds.): Debating European Citizenship (Springer, 2018), pp. 101-6 = EUDO Citizenship Forum on 19 April 2016.
• ‘German Nationality’, in: Henley & Partners/Dimitry Kochenov (eds.): QNI. Quality of Nationality Index, 3rd edn (Ideos, 2018), pp. 51-3.
• ‘Beyond the “Welcome Culture”. Projects of the New German Government on Migration, Asylum and Integration’, EU Immigration and Asylum Law and Policy am 9 March 2018.
• ‘Death Sentence for Autonomous Investment Protection Tribunals’, EULawAnalysis on 9 March 2018.
• ‘The Irony of Brexit for Immigration Control’, Verfassungsblog of 20 October 2017 = EULawAnalysis of 20 October 2017.
• ‘Mixity after Opinion 2/15: Judicial Confusion over Shared Competences’, Verfassungsblog of 31 May 2017.
• Expert Opinion on the Reform of the Common European Asylum System for the German Federal Ministry of the Interior: Minimum Requirements under EU Primary Law and International Refugee Law for Rules in Secondary Legislation on the Rejection of Applications for Asylum as Inadmissible with a view to Protection and Housing Options in Third Countries (Transit and Other Countries) or in Parts of any such Countries, January 2017.
• ‘Pitfalls of the Law, Politics and Administrative Practices in the Reform of the Common European Asylum System’, EU Immigration and Asylum Law and Policy am 9. Februar 2017.
• ‘The Limits of Transnational Scholarship on EU Law. A View from Germany’, EUI Working Paper LAW 2016/14.
• ‘Why the EU-Turkey Deal Can Be Legal and a Step in the Right Direction, Verfassungsblog and EU Immigration and Asylum Law and Policy on 9/11 March 2016.
• ‘Moving Towards Plan B: the Rejection of Refugees at the Border’, EU Immigration and Asylum Law and Policy of 28 January 2016 (also available in French: ‘Vers un Plan B : refuser l’entrée des réfugiés à la frontière?’).
• ‘Beyond Dublin – Merkel’s Vision of EU Asylum Policy’, EU Immigration and Asylum Law and Policy of 26 October 2015 (also available in French: ‘Au-delà de Dublin – La politique européenne de l’asile selon Merkel’).
• ‘The “Justice” Potential of EU Constitutional Law’, Verfassungsblog of 11 June 2015.
• ‘The Missing Link: Direct Effect, CETA/TTIP and Investor-State Dispute Settlement’, Verfassungsblog of 4 January 2015 and EULawAnalysis of 7 January 2015.
• ‘EU Free Movement as a Legal Construction – not as Social Imagination’, Verfassungsblog of 12 November 2014 and EUtopiaLaw of 13 November 2014.
• ‘Blending National Autonomy into the EU Charter. A Reply to Leonard F.M. Besselink’, Verfassungsblog of 19 August 2014.
• ‘The Solitude of European Law Made in Germany’, Verfassungsblog of 29 May 2014.
• ‘A Spring in the Desert: the German ECJ Reference on the ECB Bond Purchases’, Verfassungsblog of 12 February 2014 and EUtopiaLaw of 13 February 2014.
• ‘Who Controls the Digital Frankenstein? The Future of the Data Retention Directive’, Verfassungsblog of 17 December 2013 (English and German).
• ‘Germany’s Domestic ‘Königstein Quota System’ and EU Asylum Policy’, Verfassungsblog of 11 October 2013 (English and German).
• ‘A Trojan Horse? Challenges to the Primacy of EU Law in the Draft Agreement on Accession to the ECHR’, Verfassungsblog of 11 September 2013 and EUtopiaLaw of 12 September 2013.
• ‘The German Constitutional Court – or: the Emperor’s New Clothes’, EUtopia Law Blog of 17 September 2012 and EJIL talk of 20 September 2012.
• ‘Rescue Package for Fundamental Rights. Comments on a Proposal by Armin von Bogdandy et al.’, Verfassungsblog of 23 February 2012.
• ‘The Evolution of Supranational Differentiation: Assessing Enhanced Cooperation, the Area of Freedom, Security & Justice and the Common Foreign & Security Policy under the Treaties of Nice and Lisbon’, WHI Paper 3/2009.
• ‘The European Constitution – Notes on the National Meeting of German Public Law Assistants’, German Law Journal 6 (2005), 794–803.
• ‘The New Institutional Matrix of European Foreign Policy in the Constitutional Treaty’, WHI Paper 5/2005.
• ‘The Area of Freedom, Security and Justice in the Treaty establishing a Constitution for Europe’, WHI Paper 12/2004.

• ‘EU External Migration Policies in an Era of Global Mobilities. Intersecting Policy Universes (Sergio Carrera, Leonhard den Hertog, Marion Panizzon and Dora Kostakopoulou)’, Common Market Law Review 57 (2020), 1311-1313.
• ‘Review: Research Handbook on EU Administrative Law (Carol Harlow, Paivi Leino and Giacinto della Cananea)‘, Common Market Law Review 55 (2018), 687-689.
• ‘Review: European Security Law (Edited by Martin Trybus and Nigel White)’, European Law Review 33 (2008), 131–4.
• ‘Review: Principles of European Law (Edited by Armin von Bogdandy and Jürgen Bast)’, Common Market Law Review 44 (2007), 387–9.
• ‘Review: Repräsentation und Kompetenzverteilung (Florian Sander)’, Common Market Law Review 44 (2007), 206–9.
• ‘Review: European Constitutionalism beyond the State (Edited by Joseph H.H. Weiler and Marlene Wind)’, International Journal for Constitutional Law 4 (2006), 174–9.
• ‘Review: Bindung der Mitgliedstaaten an die Gemeinschaftsgrundrechte (Frauke Brosius-Gersdorf)’, Common Market Law Review 43 (2006), 1772–3.
• ‘Review: Europe’s Area of Freedom, Security and Justice (Edited by Neil Walker)’, European Law Review 30 (2005), 444–6.